Sent by mail, postage prepaid, to subscribers in any part of the United States or Canada.  Six dollars a year, sent, prepaid, to any foreign country.

All the back numbers of THE SUPPLEMENT, from the commencement, January 1, 1876, can be had.  Price, 10 cents each.

All the back volumes of THE SUPPLEMENT can likewise be supplied.  Two volumes are issued yearly.  Price of each volume, $2.50 stitched in paper, or $3.50 bound in stiff covers.

COMBINED RATES.—­One copy of SCIENTIFIC AMERICAN and one copy of SCIENTIFIC AMERICAN SUPPLEMENT, one year, postpaid, $7.00.

A liberal discount to booksellers, news agents, and canvassers.

MUNN & CO., PUBLISHERS,
361 BROADWAY, NEW YORK, N.Y.

* * * * *

USEFUL ENGINEERING BOOKS

Manufacturers, Agriculturists, Chemists, Engineers, Mechanics, Builders, men of leisure, and professional men, of all classes, need good books in the line of their respective callings.  Our post office department permits the transmission of books through the mails at very small cost.  A comprehensive catalogue of useful books by different authors, on more than fifty different subjects, has recently been published, for free circulation, at the office of this paper.  Subjects classified with names of author.  Persons desiring a copy have only to ask for it, and it will be mailed to them.  Address,

MUNN & CO., 361 BROADWAY, NEW YORK.

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PATENTS!

MESSRS.  MUNN & CO., in connection with the publication of the SCIENTIFIC AMERICAN, continue to examine improvements, and to act as Solicitors of Patents for Inventors.

In this line of business they have had forty-five years’ experience, and now have unequaled facilities for the preparation of Patent Drawings, Specifications, and the prosecution of Applications for Patents in the United States, Canada, and Foreign Countries.  Messrs. Munn & Co. also attend to the preparation of Caveats, Copyrights for Books, Labels, Reissues, Assignments, and Reports on Infringements of Patents.  All business intrusted to them is done with special care and promptness, on very reasonable terms.

A pamphlet sent free of charge, on application, containing full information about Patents and how to procure them; directions concerning Labels, Copyrights, Designs, Patents, Appeals, Reissues, Infringements, Assignments, Rejected Cases.  Hints on the Sale of Patents, etc.

We also send, free of charge, a Synopsis of Foreign Patent Laws, showing the cost and method of securing patents in all the principal countries of the world.

MUNN & CO., SOLICITORS OF PATENTS,
361 Broadway, New York.

BRANCH OFFICES.—­Nos. 622 and 624 F Street, Pacific Building, near 7th
Street, Washington, D.C.