One copy, one year, postage included $3 20
One copy, six months, postage included 1 60
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.
Single copies of any desired number of the SUPPLEMENT sent to one
address on receipt of 10 cents.