In reply to many interrogatories aa to what back numbers and volumes of the Scientific American can be furnished, we make the following statement: Of Volumes 1, 2 and 3—none. Of Volume i, about 20 Nos.; price 50 eta. Of Volume 5, all but 4 numbers, price, in sheets, $1. Of Volume 6, all; price in sheets, $2; bound, $2,76. Of Vol. 7, all; price sn sheets, $2; bound, $2,75