Chemistry and Physics. 309 
a a those of M. Renou, taken at the Observatory of Pare 
th n aur and allowing for the difference of longitude, it is seen 
at the principal perturbation took place at the two places at the 
same time.— Comptes Rendus, p. 329, Jan. 29, 1883. J. %. 
? a Comet of 1882.—In the Comptes Rendus of Sept. 25, 1882, 
. HOLLON and M. Gouy gave the results of their observations 
e pris 
upon this comet, and, by means of a spectroscope of on prism, 
ge that the sodium lines seen in the spectrum of the comet 
ag popineed by an amount equal to one-quarter or one-fifth of 
<a ae er ie between the two sodium lines; and hence they con- 
So a that the comet was receding from the earth w 
eh mee 61%" per second. The late astronomical calculations 
The . . ourdan give 76*" as the mean velocity of recession. 
2 sg agreement of the two results appear to prove the accu- 
= Y of the spectroscope method of measuring the recession or 
"a hg of the heavenly bodies.— Comptes Rendus, p. 371, Feb. 
3 . 
wT 
bl a The magnetising function of Steel and Nickel.—Considera- 
" lversity exists between the results of various observers upon 
ie Magnetic permeability of the magnetic metals. Hugo MeyEer 
Sives results obtained with weak magnetising forces. His method 
: experiment was to make the steel or iron cylinder the core of 
n earth inductor and to use the earth magnetic field. His obser- 
vations lead him to conclude : 
ae The magnetising function has a positive value for a dimin- 
hg magnetising force. 
tS It increases at first with the magnetising force. 
hg It increases for weak magnetising forces with the tempera- 
The value of k=2-24 for a magnetising force of f=3'096 w 
obtained for pure nickel. . 
i Rowland for cast nickel 
When the difference between the magnetising force employed by 
the two observers is considered.—Ann. der Physik und Chemie, 
No. 2, pp. 233-253, 1883. iT. 
jm.—Professor G. Carry Foster 
ie h’s determinations 
ayleigh’s results are 
