This widely circulated and splendidly illustrated paper is published weekly. Every number contains sixteen pages of useful information, and a large number of original engravings of new inventions and discoveries, representing Engineering Works, Steam Machinery, New Inventions, Novelties in Mechanics, Manufactures, Chemistry, Electricity, Telegraphy, Photography, Architecture, Agriculture, Horticulture, Natural History, etc. ALL CLASSES OF READERS find in THE SCIENTIFIC AMERICAN a popular _resume_ of the best scientific information of the day; and it is the aim of the publishers to present it in an attractive form, avoiding as much as possible abstruse terms. To every intelligent mind, this journal affords a constant supply of instructive reading. It is promotive of knowledge and progress in every community where it circulates. TERMS OF SUBSCRIPTION.--One copy of THE SCIENTIFIC AMERICAN will be sent for _one year_--52 numbers--postage prepaid, to any subscriber in the United States or Canada, on receipt of THREE DOLLARS AND TWENTY CENTS by the publishers; six months, $1.60; three months, $1.00. CLUBS.--ONE EXTRA COPY of THE SCIENTIFIC AMERICAN will be supplied gratis _for every club of five subscribers_ at $3.20 each; additional copies at same proportionate rate. Postage prepaid. One copy of THE SCIENTIFIC AMERICAN and one copy of THE SCIENTIFIC AMERICAN SUPPLEMENT will be sent for one year, postage prepaid, to any subscriber in the United States or Canada, on receipt of _seven dollars_ by the publishers. The safest way to remit is by Postal Order, Draft, or Express. Money carefully placed inside of envelopes, securely sealed, and correctly addressed, seldom goes astray, but is at the sender's risk. Address all letters and make all orders, drafts, etc., payable to MUNN & CO., 37 Park Row, New York. TO FOREIGN SUBSCRIBERS.--Under the facilities of the Postal Union, the SCIENTIFIC AMERICAN is now sent by post direct from New York, with regularity, to subscribers in Great Britain, India, Australia, and all other British colonies; to France, Austria, Belgium, Germany, Russia, and all other European States; Japan, Brazil, Mexico, and all States of Central and South America. Terms, when sent to foreign countries, Canada excepted, $4, gold, for SCIENTIFIC AMERICAN, 1 year; $9, gold, for both SCIENTIFIC AMERICAN AND SUPPLEMENT for 1 year. This includes postage, which we pay. Remit by postal order or draft to order of Munn & Co., 37 Park Row, New York. * * * * * NEW PATENT LAW FOR SPAIN, CUBA, PORTO RICO, ETC. By the terms of the New Patent Law of _Spain_, which has lately gone into operation, the citizens of the United States may obtain Spanish Patents on very favorable conditions.