The premiums in cash offered by us are as follows : Whoever sends in the largest list of subscribers, according to published terms, on or before the tenth of February, will receive $300 ; for the second list, $250 ; third list, $200 ; fourth list, $150 ; fifth list, $100; sixth list, $90 ; seventh list, $80 ; eighth list, $70; ninth list, $60; tenth list, $50; eleventh list, $40; twelfth list, $85; thirteenth list, $30; fourteenth list, 25; fifteenth list, $20. Surely these prizes are worth striving for, as either of the sums specified will be handy to have in the pocket. To those who do not compete for the cash prizes we offer the splendid large steel engraving, " Men of Progress—American Inventors," as follows: Anyone sending 10 names and $30 will receive one picture; 20 names and $50, one picture; 30 names and $75, two pictures ; 40 names and $100, three pic-tares ; 50 names and $125, four pictures. This picture is worthy of the subject, and will grace the drawing-room of any citizen of the land. We are aiming at a large subscription list and we frankly acknowledge that we can only accomplish it by the cooperation of our present patrons, who have always generously responded to our appeals. We urge them now to speak a good word for the SCIENTIFIC AMERICAN. By so doing they can induce some of their neighbors to join in making up a club. If ten or more names are sent, the subscription is $2'50 a year.