320 Scientific Intelligence. 
After several accidents had occurred during these experiments, 
worked without masks. But the greatest difficulty. to contend 
with is the short duration of the ebullition of the oxygen, and 
consequently the too short duration of the cold. 
ave attempted to measure the tesoneraunra which the boiling 
oxygen produces. For this purpose I have adopted a method of 
thermo-electric measurement which, in addition to being highl 
sensitive, allows us to record all the sudden changes of temperature 
ofthe medium. The indications of the apparatus employed have 
been poe bares ei those of a hydrogen-thermometer between 
+100° and —130° ©. The nature of the function connecting 
these Biheatious sais of an extrapolation being made. teserv- 
duced on the liberation from pressure of lique he d oxygen 
Ihave submitted nitrogen successfully to the action of this cold. 
This gas compressed, cooled in boiling oxygen, and then slightly 
released from pressure, solidifies and falls like snow in crystals of 
Feb. 1884 size.— Comptes Rendus, Dee. 31, 1883.—PAil. Mag., 
e 
y of a Magnetic prey of a portion of the Dominion 
of Riau chiefly in the Northwestern Territories ; executed in 
the ‘Aris cg 44, by Lizur. Lerroy, R.A., now General Sim 
J. roe Bs B., etc., with maps, 192 pp. 8vo.. London, 1883. 
Longisans, Geoge & Co 0.). —The magnetic observations made 
ieutenant Lefroy in the years 1842-44 have been, since thatt 
Peace River an epee Fort Good Hope on the Mackenzie 
In addition, the Deelinenary observations made in Canada and the 
United States a e also given. The discussion of the instruments 
wi ge de: Oo the varia fen in the magnetic elements observed 
large mare give the positions of the magnetic lines for the same — 
epoch over the region covered by Lieutenant Lefroy, in preparing 
which observations by Captain R. W. Has aig, Captain T. E. L 
oore and some others have oa, 5 Fai 
8. Notes on Electricity bikes ped designed as a com 
panion to Silvanus P. pson’s a eal ary Lessons by J. B. 
Murpock. 139 pp. yee otee York, 1884. "(Macmillan & Co) 
Pare 
