Chemisiry and Physics. 103 
Precipitation of water from this dense atmosphere it would descend as an 
acid rain, which attacking, at an elevated temperature, the silicates, would 
give rise to chlorids of calcium, magnesium and sodium, mingled with 
Waters of g 
Which potash has been eliminated from it by marine vegetation, and a 
nic life, offers considerations of great interest which I hope soon to 
able to develop at greater length than I have done in these few lines. 
9. On the Amount and Frequency of the Magnetic Disturbances a 
he Aurora at Point Barrow, on the Shores of the Polar Sea ; by 
te General Saprve (Proc. Brit. Assoc. Athen., No. 1559)—Point 
' Trow is the most northern cape of that part of the American continent 
Which lies between Behring’s Strait and the Makenzie River. It was the 
f H S. Plover from the summer of 1852 to the summer - 
bh he was now about to lay before the Section, and in part discuss. 
They Were furnished with nies of provisions, &e. for Sir John Frank- 
