490 Scientific Intelligence. 
as also ascribed to the action of powerful pressure. 
Petrographical Laboratory, Johns Hopkins University, March 26, 1885. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PuHysiIcs. 
n 
potable water; by Professor J. W. Matzer, F.R.S., University 
of Virginia (forming appendix D to the Annual Report of the 
lass L—Natural waters, believed from actual use to be “ 
good, wholesome character, including the regular water supply © 
ass I].—Natural waters which there seems to be fair ound 
for believing have actually caused disease on the part 0 ger 
. que i ar 
e 
duction of disease, 
Class I1I.—Natural waters of doubtful but more or less sU* 
pected character. In reference to these the medical evidence 
was insufficient to justify placing them in class II. ; 
Class 1V.—Artificially prepared waters, made by adding to 
good, wholesome water, determinate amounts of various Saetoies 
of vegetable organic matter, of natural origin, and of such kinds 
chiefly as water for human consumption is liable to come 1m con- 
tact with. : 
* Untersuchungen tiber die Entstehung der altkrystallinischen Schiefergesteine- 
Bona, 1884, p. 217. . 
