ESTES & LAURIAT 
BOSTON, MASS. 
y 
Half-Hour Recreations in Popular Science 
2d VOL.., 12 PARTS, 23 CTS. EACH. 
Twelve Consecutive Numbers, making a Complete Volume, will be sent, postpaid, as 
issued, on receipt of $2.50. 
The success attending the issue of the first volume of this serial warrants its 
continued publication. Owing to a change in the business relations of the editor and 
publishers, the previous numbers have been greatly delayed. We hope to avoid this 
difficulty in the future, and intend to issue the parts monthly, or as nearly so as 
it is possible. We are negotiating for important contributions from leading naturalists 
and writers who are deeply interested in the popularizing of natural science. It is 
the intention of the editor and publishers to make the second volume greatly superior 
to the first in interest and value ; and they trust that they may receive sufficient 
encouragement from the public to enable them to continue the series indefinitely. 
We annex a list of some of the papers which will appear in Volume II. of the 
series: 
THE TRANSMISSION OF SOUND DY THE ATMOSPHERE. By John 
Tyndall, F. R. S. 
BRAIN AND MIND. By Prof. Burt G. Wilder, of Cornell University. 
THE GLACIAL EPOCH OF OUR GLOBE. By Alex. Braun. 
THE ICE ACE IN GREAT BRITAIN. By A. Geikie, F. R. S. 
THE SUN AND THE EARTH. By Prof. Balfour Stewart, F. R. S. 
GIGANTIC CUTTLE-FISH. By W. Saville Kent, F. L. S., of the Natural 
History Department of the British Museum. 
