198 C. G. Rockwood— Recent American Earthquakes. 
shown at its maximum. The special sensitiveness of certain 
salts of silver, then, to wave-lengths of from 0-0003™™ to 0°0004™ 
and not any special solar energy or special modification of it, 
is the cause of the once-supposed peculiar “actinic power” 
this part of the spectrum. The maximum of “ heat” is found 
to be not in the ultra red but in the orange, and the curve of “ heat” 
is found to at least approximately agree with that of “light,” b 
direct experiment, and other results of equal theoretical inter- 
est, and still more practical importance begin to appear. 
The need to precede their statement in an early publication 
by some account of the means by which they were derived has 
been the occasion of this article. 
Allegheny Observatory, Dec. 23, 1880. 
Art. XXIIJ.—Notices of Recent American Earthquakes. No. 10; 
by Professor C. G. Rockwoop, Jr., Ph.D., Princeton, N. J. 
THE present article embodies such information as has been 
obtained in regard to earthquakes occurring upon the Amer'- 
can continent and adjacent islands since March 1, 1880; with 
notice of some earlier shocks not previously reported in this 
Journal. Items which depend upon single sources of informa- 
tion have their source indicated, and if regarded as at all 
doubtful are printed in smaller type. 
In addition to the persons mentioned in the notices, the 
author would express his indebtedness to J. M. Batchelder, 
Ksq., of Boston ; Prof. F. E. Nipher, of the Missouri Weather 
Service; J. H. VanDoren, Esq., of Morristown, N. J.; to the 
Superintendent of the Meteorological Service at Toronto, and 
to Pres. J. W. Dawson, of Montreal, for assistance in collect- 
ing information. 
1878, Jan. 1. An earthquake in Peru at 1.05 a. m., Lima time. 
1879, April (day not stated). Earthquakes at Chilpancigo, 00 
the west coast of Mexico, about 75 miles inland from Acapulco. 
—From Ann. Report of Dr. Fuchs in Miner. u. Petrog. Mittheil- 
ungen, Vienna, 
May 17. The shock at Vera Cruz and vicinity, previously 
Pap (xix, p. 227) as 16th or 17th, is given by Br. Fuchs as 
17th. 
June 8. A shock at 6 a, m. at Cerro de Pasco, Peru. 
Aug. 15. A shock at 6.10 a. m. at Cerro de Pasco, Peru. 
