Geology and Mineralogy. 459 
15. Sound, by Joun TyNnpait. 448 pp. 8vo. Third edition, re- 
vised and enlarged. New ‘York. 1876. (D. Appleton & Co.) 
forth. The most important new matter introduced is an account 
of the author’s investigations on the acoustic transparency of the 
atmosphere in relation to Fog-signaling. The preface contains an 
account of work done in the same line in America, and_ especially 
n 
any one’s intellect has been thus cowed in this free age, no one Is 
to be blamed but himself. 
16. Entwickelung der theoretischen Ansichten iiber die gepaar- 
ten Schwefelverbindungen von Georcr A, SMYTH (of Amherst, 
Mass.) 122 pp. 8vo. Berlin. 1876. — 
Il GroLoagy AND MINERALOGY. 
1. Report on the Geological Map of Massachusetts, prepared 
by W. O, Crospy, Assistant in the Laboratory of the Boston So- 
8 : —The map 
here referred to is one colored for the Centennial Exposition at 
Philadelphia. Mr. Crosby lays down the distribution of Norian, 
berg formation (1 
‘ ower or upper € 
and quartzyte, anaes to be folded by the author with the Mont- 
