BACK NUMBERS AND VOLUMES—In reply to many interrogatories as to what back numbers and volumes of the Scientittc American can be furnished, we make the following statement:—Of Volumes 1, 2 3 and 4—none. Of Vol. 6, all but six numbers, price, in sheets, $1; bound, $175. Of Volume 6, all; price in sheets, $2; bound, $2,76. Of Vol. 7 all; price in sheets, $2; bound, $2,75. Of Vol. 8, all the back numbers subsequent to No. 27, but none previous. PATENT CLAIMS—Persons desiring the claims Of any invention which has been patented within fourteen years, can obtain a copy by addressing a letter to this office—stating the name of the pa-tentee, and enclosingone dollar as fee for Copying.