It is surprising how many large enterprises and fortunes depend upon some few simple trade secrets the knowledge of which has baffled competition and crushed all rivalry. The jealous care with which special information in trade and manufacture is guarded frequently renders it a monumental task to procure a single receipt or formula. Some idea, then, may be formed of the vast amount of labor and expense necessary to compile a work of this character. Books of recipes are quite numerous, but to the average person the good they contain is too often buried beneath a mass of wordy rubbish. In the preparation of this work the object has been to present all the best as well as the latest practical receipts, prescriptions, and trade secrets. Over a quarter of a million pages of patent-​office reports, encyclopedias, trade journals, receipt books, and other special publications have been carefully scrutinized. To the knowledge obtained from them we include the original matter procured from tradesmen, chemists, and the published works and private practice of some of the most eminent physicians both in this country and Europe, a greater portion of which has never before appeared in print; all of which has been carefully tested where any doubt existed. It will be found that few, if any, misleading directions have been given. The prescriptions have been reproduced, after careful thought, in the form in which they were originally written. In having them filled patronize only honest and capable druggists. In testing the recipes follow the directions with rigid care, and practice on a small quantity of the article until you get it right. Realizing that perfection in anything has never been attained, yet we believe that the work contains more really practical information for use by the masses in every-​day life than any similar publication.

Chicago, March, 1889. THE AUTHOR.

Gelatine Copying Pad.

[HEKTOGRAPH.]

By this process a letter, postal card, drawing, or other manuscript can be duplicated from sixty to one hundred times from one original. Reproductions from the copying pad are now admitted in the mails as third-​class matter, i. e., one cent for every two ounces or fraction thereof. A soft, gelatinous composition, similar to that used in making printers’ rollers, is made and poured into shallow pans of the required size. The pans should be made of stout zinc one-half inch deep on the inside, with a lid or cover. The length and breadth of the pans is determined by the class of copying to be done. Always make the pan slightly larger than the paper used. The three sizes given below will answer most purposes: