134 Scientific Intelligence. 
observable through the centre of the tube in the form of a wave line 
On repeating this experiment I ascertained that the vacuum in the 
as very much deteriorated. I could no longer produce that peculiar — 
bubbling in the ball of the apparatus which is always attainable by — 
gently heating the tube with the warmth of the hand; this bubbling was 
originally very sensibly perceptible in the tube I now exhibit when | first 
received it from the maker, Mr. Casella. Ihave repeated the experiment — 
with other water-hammers, and always with the same result; but I havé 
not yet opened one to examine whether the vapor has been decomposed, 
and gas evolved. ni? 
Il, GEOLOGY. gig 
1. On Marcou’s “ Geology of North America ;” by Prof. Acass—t . 
United States and British North America by H. D. Rogers, also beating 
3 ae 
date 1855, and Hall’s and Leslie’s Map of the country west of the Mis 
sissipp! river, published with the 1st vol. of Emory’s Report in 1857, 
nself ‘ound. a3 
’ A comparison for instance, of the manner in which the voleanie al "4 
are dotted over New Mexico, Sonora, and Lower California, a8 WO oy 
in California, Oregon and Washington Territories by Hall and #°8"” 
ry 
