=_Foreign Patents._=--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. American inventors should bear in mind that, as a general rule, any invention that is valuable to the patentee in this country is worth equally as much in England and some other foreign countries. Five patents--embracing Canadian, English, German, French, and Belgian--will secure to an inventor the exclusive monopoly to his discovery among about ONE HUNDRED AND FIFTY MILLIONS of the most intelligent people in the world. The facilities of business and steam communication are such that patents can be obtained abroad by our citizens almost as easily as at home. The expense to apply for an English patent is $75; German, $100; French, $100; Belgian, $100; Canadian, $50. =_Copies of Patents._=--Persons desiring any patent issued from 1836 to November 26, 1867, can be supplied with official copies at reasonable cost, the price depending upon the extent of drawings and length of specifications. Any patent issued since November 27, 1867, at which time the Patent Office commenced printing the drawings and specifications, may be had by remitting to this office $1. A copy of the claims of any patent issued since 1836 will be furnished for $1. When ordering copies, please to remit for the same as above, and state name of patentee, title of invention, and date of patent. A pamphlet, containing full directions for obtaining United States patents sent free. A handsomely bound Reference Book, gilt edges, contains 140 pages and many engravings and tables important to every patentee and mechanic, and is a useful hand book of reference for everybody. Price 25 cents, mailed free. Address =MUNN & CO.=, Publishers SCIENTIFIC AMERICAN, 37 Park Row, N. Y. _BRANCH OFFICE--Corner of F and 7th Streets, Washington, D. C._ ---------------------------------------------------------------------- The "Scientific American" is printed with CHAS. ENEU JOHNSON & CO.'S INK. Tenth and Lombard Sts., Philadelphia, and 59 Gold St., New York. * * * * * TRANSCRIBER'S NOTES Obvious punctuation errors have been corrected. Spelling inconsistencies have been retained. On page 83, the clause "It has an independent extinguisher for the smaller wick tube" had "ndependent" in the original. On page 91, the ad reading "The Turbine Wheel made by Risdon & Co., Mt. Holly, N. J., gave the best results at Centennial tests." had "tets" in the original.