The next operation which claims attention is the drilling of the pearls. I neglected to inspect this part of the business; but have been informed that much admiration is excited, both by the dexterity of the artist, and the rude simplicity of the machinery which he employs. A block of wood, of the form of an inverted cone, is raised upon three feet about twelve inches from the ground. Small holes or pits of various sizes are cut in the upper flat surface, for the reception of the pearls. The driller sits on his haunches close to this machine, which is called a vadeagrum. The pearls are driven steady into their sockets by a piece of iron with flat sides, about one inch and a half in length. A well tempered needle is fixed in a reed five inches long, with an iron point at the other end, formed to play in the socket of a cocoanut shell, which presses on the forehead of the driller. A bow is formed of a piece of bamboo and a string. The workman brings his right knee in a line with the vadeagrum, and places on it a small cup, formed of part of a cocoanut shell, which is filled with water to moderate the heat of friction. He bends his head over the machine, and applying the point of the needle to a pearl sunk in one of the pits, drills with great facility, every now and then dexterously dipping the little finger of his right hand in the water, and applying it to the needle, without impeding the operation. In this manner he bores a pearl in the space of two or three minutes; and in the course of a day perforates three hundred small or six hundred large pearls. The needle is frequently sharpened with oil on a stone slab, and sometimes, before the operation is performed, is heated in the flame of a lamp.

The large pearls are generally drilled first, in order to bring the hand in to work with more ease on those of a smaller size; and pearls less than a grain of mustard-seed are pierced with little difficulty.

After the pearls have been drilled, they must be immediately washed in salt and water, to prevent the stains which would otherwise be occasioned by the perforating instrument.

A quaint description of pearl drilling was given by Anselmus de Boot in 1609.^[419]

Since all are not aware of the manner in which pearls are perforated, I wish here to give an account of the method. The handle. A, is held with the left hand, and then the handle, B, of the bow is pushed back and forth with the right hand, so that there is a reciprocal movement of the lance AC. The extreme end, C, has a needle, not so sharp as to come to a point, but slightly blunted. The needle is placed on the pearl which is to be perforated. If the pearls are too small to be held, they are fastened in the case, D, with a small hammer of soft wood, lest they should slip. The board is inclosed on every side by strips of wood so that the water which comes from the pearls shall not flow off. The bow being moved, the needle penetrates and pierces the pearl and it is not corroded by the water.

A mythical story, but a pleasant one, is told of a great pearl collector who had owned a wonderful pear-shaped pearl for many years and had absolutely failed to find any match for it. After years of fruitless search he was at last rewarded by finding an absolutely perfect mate. He took this to his favorite jeweler in one of the great capitals of Europe, and ordered the new gem to be pierced to match the other so that both could be set. The jeweler called a small German boy from an adjoining workshop, simply saying, “Jakey, drill this pearl to match the other.” The collector was dumfounded that no caution should be given to the boy when so important a piece of work was intrusted to his care. Scarcely had the boy left the room when the collector inquired of the jeweler, almost in consternation, “How can you trust so valuable a pearl to so small a boy without a word of caution?” To this the dealer replied: “Jakey is the most careful pearl driller I have ever known. I know that there will be no failure in the drilling. I have never cautioned him about such work. He never has drilled a pearl wrong. Had I warned him of the value of the gem or told him how important a piece of work he was doing, he probably would have become nervous and, as a result, your pearl would have been cracked.” The conversation had scarcely been completed before Jakey returned with the pearl as beautifully drilled as the original one which it matched.

In the Orient and elsewhere, when it is considered desirable to mount a pearl so that it shall not turn, especially when only one part of the pearl is perfect and that is to remain outside, the drill hole is sometimes made square, that is to say, drilled round and then reamed out with a small saw until it becomes square, when a square wire is inserted; or else the pearl is first drilled with a tiny round hole and this is then reamed out until it is triangular, when a triangular wire is introduced. This method is sometimes used for studs or ring-settings.

In setting pearls with points or claws on the wire or band of a ring, the pearls are drilled only half way through. A gold pin is then inserted, and sometimes a thread is cut into the pearl itself; it is secured by means of gum mastic or some other strong gum. Occasionally, to add greater strength, a side pin is put in, so that the pearl is drilled with two bits of metal, which penetrate the one side in a perfectly straight line and the other at an angle of about twenty-five or thirty degrees (this is called side-pegging). This gives more strength and firmness to the pearl itself, and prevents it from twisting or twining and becoming loose. Sometimes the pearl hole is drilled so that the opening is that of a screw-thread, in order to hold it to the earring, the stud, or the ring. The gold pin which is inserted to attach the pearl to the ring or stud has a screw-thread also, and the peg or pin is screwed on as well as secured.

An ingenious method, termed “keying,” for securing the peg in pearls to be set on rings or studs, consists in drilling a hole half through the pearl and then two smaller holes or grooves on each side of the first. Cutting tools of a T-shape are now introduced into the aperture and worked about until the pearl is undercut all around, so that when a peg with a cross-piece is inserted, the latter can be turned within the pearl until it sets at right angles with the widest part of the aperture. In this way the peg is permanently secured and cannot slip out.

The fact that in recent years more pearls have appeared in necklaces that are irregularly bored, that the bore holes are so large that they are plugged with mother-of-pearl, or that one meets with pearls in which a plug has been placed in the side immediately in the center between the two drill holes, is due to the fact that the great demand has resulted in the destruction of many oriental ornaments in which the pearls were drilled in various ways, as well as in the destruction of the different Magyar and other semi-official jewels of eastern Europe.

The most primitive known drills were the flint drills, made by the North American Indians by chipping chert or flint-like minerals to a fine point. With these rude instruments a large, irregular hole was made, which generally measured several times the diameter of the fine drill hole made by a modern pearl driller with an improved drill. The Indians are also said to have used hot copper drills for boring holes.

The earliest, and still a very general and perhaps the best way of drilling pearls, is by means of the bow- or fiddle-drill. This method has been used in a more or less perfected form by all the aboriginal peoples of the New World from Iceland to Tierra del Fuego. But as none of these peoples were familiar with fine, hard steel, they scarcely ever succeeded in making drill holes as fine as those that can be produced by the use of tempered steel. By the latter means, pearls half an inch in diameter are often drilled entirely through with an aperture no larger than a thin bit of straw.

The largest and finest pearls are frequently drilled with the smallest holes, as the slightest loss in weight means a diminution in value. Then, too, a pearl with a small drill hole is not so liable to shift on the string, and thus is less likely to cut the silk thread which holds the pearls together.

It would be difficult to enumerate all the tricks to which some jewelers now resort in order to utilize every fragment of a pearl they can lay their hands on. Some of them are wonderfully clever at reconstruction, but to the woman who loves pearls, nothing can take the place of the soft, beautiful, round gem, with its natural surface.

In sorting pearls for the smaller necklaces, it is customary to open up a number of dozen bunches of the East Indian pearls as they are sent from the East, strung, the ends fastened together in bunches, and then sealed. These pearls are placed on a table and are first arranged according to color and luster on the sorting board. They are then grouped according to size and graduation, the greatest care being exercised in the selection for color, luster, and form. In this way ten necklaces may be re-strung into ten others, the necklaces probably being improved as regards selection, or else better arranged for the uses to which the jeweler wishes to put them.

In the case of the larger necklaces, it frequently requires many years of selection and arrangement before one becomes perfect enough to pass the criticism or suit the fancy of the jeweler.

We have no record as to when the first pearl necklace was strung, nor have we a definite record of the first use of silk for stringing a necklace. The earliest illustration that we have been able to obtain of the use of pearls in the form of a necklace is the one from Susa, in which the pearls were secured with gold. A Syrian necklace, dating about one or two centuries before Christ, was strung by means of a bronze wire. We will endeavor to give a few facts on the interesting process of preparing pearls for wearing.

Pearl stringing is an art, easy as the process may seem, and it is interesting to note the precision, care, and delicacy with which the pearl stringer performs his task. The first step is to grade the pearls according to their size and color, so that they may produce the best possible effect. The largest and finest pearl is placed in the center; alongside of this, on each side, are laid the two pearls next in size which are the most nearly alike in form and hue; and so on to the end of the necklace. This grouping requires both experience and judgment, and is of great importance, since the value of the pearls is often considerably enhanced by a proper arrangement. A skilful stringer is able to grade them so cleverly that only a trifling difference will be found in the weight of the two halves of a necklace.

The stringing process consists in securing the end pearl by a knot to the diamond, pearl, or other clasp which may be used. When a necklace is being strung, the thread is passed through the metal eye, or pearl, or other object that serves as a clasp. It is then tied with one knot, passed through the next pearl, and knotted between that and the second pearl, and sometimes between the second and the third, thus making the joint doubly secure. The other pearls are then strung in their order, a knot being placed after each fifth, fourth, third, or second pearl, or, should there not be enough to give a proper length to the necklace, between each single pearl. The deftness with which the knot is tied so as not to hold the pearl too tightly, and risk the breaking of the thread, and the precision with which forty, fifty, and even sometimes several hundred knots are made on a single string, is a pleasing operation to witness, and requires the greatest care and nicety of touch. If knots are made frequently between the pearls, there is less danger of losing them should the thread break, as only one or two can fall off; sometimes, indeed, when the drill holes are very small, the silk thread, waxed or unwaxed, fits so closely that the pearl does not become detached even when the thread breaks.

The thread used is invariably of silk of the highest standard of purity, strength, and texture, undyed, and not containing any chemicals. Two or three of these threads are held together, then with a knife the edges are very carefully scraped till the combined material of the three threads is less than the thickness of one. Some use a needle to scrape or fray to a sharp point. Then this point is stiffened by means of “white glue,” the best material of this kind being pure gum arabic dissolved in water. A little of this is rubbed on the pointed threads. It stiffens in a moment, then the pearls are passed on, one after the other. If the pearls to be strung are already on a necklace, this process is simplified by the unknotting of the end of the necklace to be re-strung; two or three of the pearls are slid on to the new string, the ends or points of the new necklace thread are twisted together with the old ends and the pearls are simply transferred.

Frequently the holes have been drilled so as to leave the rims rather sharp; in this way the thread may be frayed out or even cut. This sharp edge can easily be removed by careful reaming. Silk of pure quality is the best material known for stringing pearls. A series of experiments were made with every available fiber of sufficient durability from every quarter of the globe, but silk alone was found to possess the strength, the flexibility, and the smoothness necessary to permit a very fine set of threads to pass through an opening as small as the drill hole of a pearl. In the case of a long chain or sautoire, more than three hundred pearls will be strung on a single row, one of over eighty inches in length containing over three hundred pearls, and it requires a degree of neatness and patience that few possess to do this in exactly the right way, so that the thread may not be cut, that the pearls may not be too tightly strung, and that the ends shall be carefully attached at the clasp, so that the necklace may hang well and there may be no danger of the ends breaking loose.

According to the frequency with which it is worn, a necklace should be re-strung every three, six, or twelve months. The proper time for re-stringing can generally be determined by the stretching of the thread so that it can be seen either between the pearls or at either end, giving the impression that one or more pearls are missing. A newly strung necklace is taut.

Where a collar is from thirteen to fourteen inches in length, there are frequently twenty-three rows of pearls, kept straight by four jeweled bars, and sometimes from ten to twenty-five pearls in a section between a bar. This would mean that there are more than two thousand pearls in a collar of small pearls. When one considers that at each bar and at the catch and clasp of the collar it is necessary to make a knotting, it is not surprising that it requires from three to four days’ time of a very expert pearl stringer to string or re-string such a pearl collar. A splendid example of such a twenty-three-row collar is that belonging to Señora Diaz, wife of the President of the Republic of Mexico.^[420]

Frequent stringing may sometimes serve as a protection for pearls, as, if wax is used, the drill hole is likely to become coated with wax from the thread, and this prevents the absorption by the pearl of perspiration or moisture of any kind through the thread. Indeed, the thread itself, when waxed, does not readily absorb moisture, and as the interior of the pearl also becomes waxed, this serves to protect it from the absorption of humidity of any kind.

In making pearl necklets or muff-chains, a piece of gold wire of the proper strength and pliability is taken. This wire is passed through the hole of the pearl and then cleverly bent into a loop on each side and firmly soldered. It is important that the wire should be very slightly smaller than the dimension of the hole in the pearl so that it may fit closely. Sometimes, instead of this method, a ring is soldered to one end of the wire before this is passed through the pearl, the other end being then secured in the manner described above. Still another method is occasionally employed; in this a piece of the wire is bent into a ring, but not quite closed, the aperture being just large enough to admit the wire that has traversed the pearl; in this way the wire can be introduced into the opening in the ring, which grips it tightly, and is then soldered to it. In many cases two small rings are strung on the wire on each side of the pearl before the loops are made, so that they interpose between the latter and the pearl itself. This serves to protect the sides of the pearl, as there is otherwise some danger that the hole may become chipped or ragged; the same result can be obtained if small caps, closely fitting the pearl, are used instead of the rings. This is, however, only possible when the pearl is quite round, and in this case the effect produced is often very attractive.

Many of the pearls set as rings and studs are no longer set in points, but are set upon a peg, or are “pegged,” as it is termed. Setting a pearl in claws generally hides more than one half of the entire sphere. But if the pearl is not properly secured upon the peg, it will occasionally fall off. However, this can be obviated to a great extent by attaching the pearl to a double peg which keeps it from turning and also prevents its falling off. Pearls have occasionally been damaged with the shellac used, or when the gold peg on which the pearl is placed was too hot.

In mounting very small pearls as link chains so as to form a continuous pearly rope without any break in the way of gold links, occasionally V-shaped cavities are drilled into each end of the pearl, and the setting itself is hidden in this V-shaped cavity. This is only done where the pearls are small and not of great value.

The jeweler, in setting pearls, must use the greatest possible care, first, in cutting away the settings, as they are fastened to the pearl, not to scratch or mar it; and then, when he files the settings, not to allow the file to touch the pearl, as both the steel tool and the file would injure it. He must particularly avoid placing the pearl too close to a diamond, ruby, or other precious stone; for, even if the pearl only slightly touches the gem against which it is set, a knock of the hand may mar the pearl’s surface. More especially, as pearls are set at present, “pegged” and without points, it is of the greatest importance that they be worn in such a way that they may not touch the unexposed edges of any precious stones, as this also would injure the pearls. For lack of this precaution fine pearls have frequently been harmed.

A large jewelry firm has under consideration the following pearl order: Any workman who in any way mutilates a pearl by filing, imperfect drilling or shaping, or in any way affects the shape of a pearl, without the authority of the foreman, will be called upon to pay for the same.

As pearls are natural objects, any change of the same to fit the setting, or for attachment to any gold object, mutilates the gem and greatly affects its value. If belonging to a customer, this frequently means its replacement, often at a great cost to the jeweler.

Pearl “blisters” frequently have the appearance of being empty; they are generally filled with a fluid, either water or the product of animal and vegetable decomposition. These contents usually emit a peculiar and unpleasant odor. As the exterior of the inclosure gradually wears away and disappears, the contents of the blister are slowly absorbed by the shell itself, and any organic or insoluble substances are deposited on its inner surface.

Thus, when a shell shows any protuberance on this surface, the peeler will cut or scrape away a portion of the decaying shell behind the spot. Should he discover the hole of a borer, he lays the shell aside; but if he finds it to be perfect at this spot, it is evident that the inclusion came from within, and frequently it turns out to be an included pearl. This is removed by breaking the shell, or by cutting around the protuberance very near to its edge, and then breaking away the shell. The pearl is often visible, and layer after layer of the covering mass is removed with the greatest care by the peeler, who is rewarded by bringing to light pearls of various qualities, and frequently those of great value.

An instance in which, by opening a pearl blister, the speculator received a good reward is given by Streeter, who says: “The Harriet had the good luck to find, in 1882, a pearl 103 grains in weight, which was inclosed in a huge blister. It was a fine bouton, of splendid color in the upper portion, but a trifle chalky below. This was attributed to the admission of salt water into the shell through a hole made by a borer which happened to pierce the shell just where the pearl lay, and had penetrated the latter for almost a quarter of an inch.”

Sometimes pearl masses are hollow. Barbot^[421] mentions that a French merchant residing in Mexico, having bought one of these pieces from a fisherman at a low price, resolved to satisfy his curiosity by finding out what was inside. He split it in two parts and was agreeably surprised to find a pearl weighing 14¼ carats (57 grains), so round, of such good water, and such fine orient, that he sold it in Paris for nearly 5000 francs ($1000) in 1850.

Seed-pearl work was introduced into the United States, about seventy years ago, by Henry Dubosq, who had studied the methods employed in Europe and has been succeeded in this industry by his son, Augustus Dubosq. The father bought a large quantity of English seed-pearl jewelry, brought it to this country, and hired a number of girls to take it apart carefully and re-string it with white horsehair, to learn how it was made. With no more teaching, he established an industry that has already lasted for three score and ten years.

Seed-pearl jewelry was most in vogue from the year 1840 to 1860. It was generally sold in sets, in a case consisting of a collar, two bracelets, two earrings, a small brooch, and a large spray or corsage ornament. If the object was almost round, occasionally there was a larger central pearl, weighing from one to five grains, usually a button pearl; or, if the ornament was elongated, there were generally three larger pearls. These sometimes possessed a fairly good luster. Seed-pearl jewelry was at one time so popular, and the values were so small in this country, that a $1000 seed-pearl set formed a principal feature of the Tiffany exhibit at the International Exposition held at the Crystal Palace, New York, in 1855.

Seed-pearl tiaras sell for from $75 to $200 or $300 each. The work is almost entirely done by girls, either German or of German origin. As labor is higher and pearls have advanced in price, none of the old work could now be duplicated for the amount it cost twenty or thirty years ago. The stringing of the pearls on the English scroll means probably twelve hours of continuous work. An efficient pearl worker receives $3.50 a day, which consists of not more than eight hours, as, owing to the very trying character of the work, clear daylight is necessary to see the holes in the small pearls and in the mother-of-pearl shell.

The foundation of all seed-pearl work is mother-of-pearl. The shell is brought in thin plates, measuring from one and one half to two and one half inches square. One of the most popular and attractive patterns is the English scroll. If a design is to be repeated, a brass figure is made. For the fabrication of a brooch, for instance, a design is first made by drawing on a paper or cardboard; then a brass plate or pattern is cut out, leaving spaces wherever there are to be no pearls. After this a slab of stock mother-of-pearl, nearest the size of the brass plate, is selected, and is sawn out, using the brass plate as a guide for the outlines. The mother-of-pearl is then pierced wherever a pearl is to be secured, and the pearls for its embellishment are chosen, and are strung onto the mother-of-pearl outlines with a special horsehair thread. All the work that remains for the jeweler is the addition of a pin or catch on the back. A representation is given of the designs, the brass plate, the mother-of-pearl, the horsehair, the pearls, and the completed brooch made by this model.

Fine horsehair is used for stringing seed-pearls, because the holes drilled in them are usually too small to admit of the use of silk, and it is very important that what is known as pulled hair, taken from a living horse, should be used, as otherwise the hair is too brittle. This hair, in bunches of from eight to fourteen inches in length, is sold at an average price of $1.50 a pound, and frequently only one ounce is selected for use from the entire pound.

All the pearls used by the seed-pearl workers are purchased in strings and bunches; the finest are those known as the Chinese seed-pearls; they are drilled and strung in bunches, weighing three ounces, and are worth $40 an ounce. They are drilled with so fine an aperture that silk will not pass through the pearl, and only horsehair can be used. The Indian Madras pearls, however, have a larger drill hole and can be strung with silk; they are at present worth from eight to fifteen cents a grain, that is, $48 to $90 per ounce.

Immense quantities of these very minute pearls are also used in bunches or strings, sometimes as many as twenty or thirty strings being grouped together and either bound straight or else twisted into veritable ropes of pearls.

Seed-pearls are sold by the ounce, a single ounce frequently containing as many as 9000,—that is, fifteen pearls to the pearl grain or sixty to the carat,—selling for from $48 to $60 an ounce. Naturally, some of these pearls are even smaller than this, but the average is maintained by those that are a little larger.

Pearls as small as 100 to a diamond carat are drilled and used in seed-pearl work. Diamonds, rubies, and even sapphires, however, are cut in brilliant form when they are as small as 250 to 300 to the carat, or 45,000 to the ounce. The price of these small pearls, however, is only from eight to fifteen cents per carat, whereas diamonds of this size are worth from $200 to $300, their value being three times that of those weighing one sixteenth to one eighth carat each. This is due to the fact that the labor expended in cutting the smaller diamonds is much greater than that bestowed upon the pearls, which simply require drilling and not cutting.

“Half-pearl,” as we have mentioned, is the name given to such pearls as are round and spherically domed and are either somewhat flat or almost the shape of one half of a whole pearl of the same diameter. They are produced in two ways: some are cut away as hemispheres from the inner surface of the shell of the pearl-mussel, but more usually they are the better portions of defective whole pearls which are sawn or split by hand into two “halves” with a minute saw, the defective part being rejected altogether or classified as inferior half-pearl, while the better half is classified as a I or II quality half-pearl. Frequently a fine specimen is obtained from an elongated pearl, and sometimes two, three, or even four half-pearls are secured from the various bright parts of a round pearl. In splitting half-pearls, the pearl to be operated upon is held by hand in a kind of grooved vice or pincers and sawn through with a very fine saw; this process is at once simple, rapid, and of insignificant cost.

Only pearls which cannot be cut are filed. In this process the poorer side of the pearl in question is laid upon the file, and the operator takes a piece of ordinary hard wood, so formed that he can grasp it firmly in his hand, presses it down upon the pearl, and rubs the latter on the file, removing all but the good side. In this way a half-pearl is produced.

The smaller half-pearls are from .5 to .75 millimeters in diameter, and an ordinary ounce of half-pearl material will number 18,000. Of the manufactured half-pearls there are, on an average, 20,528 to an ounce.

The half-pearl industry is largely carried on in Idar, on the Nahe River, and in Oberstein, in the Duchy of Oldenburg, Germany. The pearls are usually purchased from London or Paris houses in lots valued up to $12,000 or more, although some of the firms buy directly from India. In Idar about one hundred people are employed in this industry. Frequently it is pursued m the home of the manufacturer, who may employ from one to a dozen or more workers. These generally include a sorter or arranger, and a marker to indicate the part of the pearl which should be sawn off. There is also a trimmer or one who finally adjusts the pearls.

An unusually clever bit of deception was practised by an American pearl fisher who had found two pearl blisters of almost identical size. Both of these blisters were hollow, and were alike in form. The pearl dealer very cleverly polished down both sides, rounded off the edges, cemented the two backs together, and except for a tiny edge they had all the appearance of a drop pearl that was fairly perfect on both sides. It required but a little heating to separate the parts and show the deception.

In setting half-pearls, they are generally selected from large lots with great care as to their being of uniform size. A circular place for the setting is often drilled with a steel drill, either for several or for a single one. The half-pearl is frequently placed on one or more tiny disks of paper, to give it the exact height in the setting, and the edge of gold is rubbed up against the pearl, which is thus secured in its place; or else tiny edges of gold are left projecting between each pearl. These are pressed down after the pearl is in place. This process requires great delicacy and skill and is frequently employed in the decoration of pearl lockets and watches. In some of the cheaper work, the half-pearls are cemented into the shallow disks that were drilled for them, but frequently they are secured by metal points skilfully raised out of the disks in which the pearls are set, and then pressed down to hold the latter in place. Although apparently frailly set, it is surprising that half-pearl ornaments have been owned for more than a century, scarcely a pearl dropping out; and even if one or two pearls should be lost from the piece of jewelry, the expense of replacing them is not very great. They are often not as safely set when they are mounted with diamonds, rubies, or other stones, more especially in rounded rings or bracelets.

In drilling gold for the setting of half-pearls, where the hole must not be carried right through the metal, a so-called “pearl drill” is used. This is designed to cut a hole with a flat base in comparatively thin layers of metal without disfiguring the opposite side, a task that can easily be accomplished if care be taken not to drill deeper than is strictly necessary for the safe adjustment of the pearl. For the construction of this drill a piece of round steel wire of suitable size is chosen; this is hammered flat at one end and then filed away at each side, leaving a small spike standing in the center, which projects a little beyond the cutting edges and acts as a pivot on which the drill revolves. The steel on both sides of this spike is filed down to a fine edge, care being taken to preserve the horizontal line, so that when the spike is embedded in the metal both cutting edges come into play simultaneously. If the drill is in good condition, it does its work very rapidly, since it is used in an upright drill-stock, whose weight gives a uniform and constant pressure. A good range of sizes of this drill should be kept ready for use, so that one may be found to suit the dimensions of any given pearl. This is essential in order to make an opening just large enough to hold the gem, so that it may fit tightly, without the necessity of reaming out the hole.

Half-pearls were frequently used with the most pleasing effect in the decoration of antique watches. A number of remarkable examples of this type are among the collection of antique watches of Henry Walters of Baltimore. This collection had been acquired by Tiffany & Co. after the sale of the San Donato Palace, the watches having been withdrawn from the prince’s collection by his sister sometime before the sale.

In mounting pearls on gold, a white paste is sometimes employed in half-pearl mounting, which is called by the French jewelers gouache. This substance contains white lead, and its use is liable to be injurious to the workmen, cases of lead colic having been recently recognized as thus produced. This subject has lately (1907) been brought forward at the Société Médicale des Hôpitaux in Paris. The cases were at first mistaken for appendicitis, but proved to be well-marked cases of lead poisoning. They had not been reported previously, and are evidently not frequent, those noted being confined to instances in which the employees had carelessly been in the habit of removing an excess of the paste with the tongue.

Pearls that are constantly worn with judicious care do not seem to deteriorate in any way. By judicious care we mean that pearls should not be dropped or thrown down violently or placed on any substance which is likely to act injuriously on the surface of the pearl itself.

Strings of pearls should never be dipped into water or solutions of any kind, because the string which passes through them is likely to absorb and to draw the liquid into the pearl, and as the pearl is made up of many concentric layers, it is quite possible that, through capillary action, some liquid, either pure, or stained with a foreign substance, might be brought into the pearl, which would in this way eventually become discolored. Rings and brooches containing half-pearls frequently change color from this cause; but contact with the skin, or with lace, or with fabrics which are not stained with certain chemical solutions, seems to have no injurious effect upon pearls.

It is quite possible that in some instances where pearls which have been inherited are thought to have changed and lost their beauty, this belief has been owing to an exaggerated opinion of their quality on the part of those who expected to inherit them and who never had the opportunity to examine them carefully. In other words, in many cases where pearls are believed to have lost their luster, to have died, or partly died, there seems, from the personal observation of the writer, to be little doubt that they never were really fine pearls, and that no change had actually taken place in them. That pearls change but slightly is evidenced by the fact that a splendid necklace belonging to the Empress Eugenie, which was purchased about the year 1860, is in as good condition to-day as when it first passed into the hands of the unfortunate empress of the Second Empire. Many of the pearls in the royal treasury in Vienna that belonged to Maria Theresa, and those that were disposed of at the sale of the French crown jewels in 1886, as well as the pearls that are in the imperial collection at St. Petersburg, do not seem to show any appreciable evidence of age.

The pearl is of a lower hardness than any of the precious or semiprecious stones, and almost as soft as malachite, though not so friable or liable to break as is that mineral; nevertheless, it is in many ways one of the most indestructible of natural objects of the low hardness. Still, pearls, and especially fine pearls, require some care; but, if the same attention is accorded them as would be given to a fine piece of lace, velvet, or other fabric, or to a fine jewel, they will last for a number of generations. If, however, pearls are worn at all times without removal, if they are worn in the bath, if they are thrown on a dressing-table, dropped on the floor, or otherwise ill-treated, if they are worn on dusty automobile rides, in bicycle riding, or during other gymnastic or violent exercise, it is inevitable that their sides will rub together and wear one another away. If they are worn in the bath or in swimming, the silk string which holds them, should it become soaked, may draw some of the water, accompanied perhaps with dust and perspiration, through the drill hole into the center of the pearl, and this is likely to be absorbed in turn by the various layers of the pearl, in some instances undoubtedly affecting the color, changing it to a yellow or a gray. It would be well not to wear pearls under the exceptional conditions above mentioned; and, if they are carefully wiped at times, so as to remove any perspiration or dust, their color is not likely to be affected for a long period of time.

Dr. George Harley writes in the “Proceedings of the Royal Society,” March 1, 1888, p. 463:

On one occasion being desirous to crush into powder a split-pea sized pearl, we folded it between two plies of note-paper, turned up the corner of the carpet, and placing it on the hard, bare floor, stood upon it with all our weight. Yet, notwithstanding that we weigh over twelve stone, we failed to make any impression whatever upon the pearl, and even stamping upon it with the heel of our boot did not suffice so much as to fracture it. It was accordingly given to the servant to break with a hammer, and on his return he informed us that on attempting to break it with the hammer against the pantry table, all he succeeded in doing was to make the pearl pierce through the paper and sink into the wooden table, just as if it had been the top part of an iron nail, and that it was not until he had given it a hard blow with the hammer against the bottom of a flat-iron that he succeeded in breaking it.

As the foregoing and other notes had appeared on this subject, the author was led to observe that pearls are possessed of greater durability than is generally supposed. In order to demonstrate this satisfactorily, he took a number of American pearls and placed them upon different kinds of woods, such as white and yellow pine, white oak, teak, ash, cherry, chestnut, and rosewood. He then stood upon them, thus bringing a weight of more than two hundred pounds to bear upon them by means of his heel. The pearls were driven into the different woods, with the single exception of the rosewood, which offered greater resistance so that the pearl only entered partly. In but one instance did a pearl suffer by a slight scaling off. This shows the strength of the many concentric layers, both mineral and vegetable.

This does not signify that pearls should be stepped upon, trodden upon, or thrown about, as it is not unlikely that a pearl would crack if it should fall from some height upon a hardwood or stone floor.

It is believed by many that wrapping pearls in dyed velvets or in fatty woolen materials, and locking them up in safe-deposit vaults, may slightly change them. On the other hand, there is no doubt that sunlight will bleach a pearl, and hence it is that wearing them in the light and air cannot injuriously affect them.

For cleaning pearls, first rub them with a cloth dipped in alcohol diluted with warm (not hot) water, or in a weak solution of soap and water, then dip another cloth in clean water and rub the pearls until they are dry. Be careful not to leave them wet. Either salt, rice, pearl-powder, or some exceedingly soft substance may aid in cleaning them, but no abrasive such as ground pumice, electro-silicon, or any powder that is sold as a polishing powder, should be used.