Geology and Mineralogy. 71 
800th part of the velocity of the earth in its path.—Ann, der 
Physik und Chemie, 1895, No. 5, pp. 65-81. Ba ie 
3. Wave length of the Ultra Violet lines of Aluminium.—C. 
RuncGe has made a determination of the strong line of aluminium 
in the ultra violet by means of a Rowland concave grating of a 
meter radius. The whole apparatus was placed in an air-tight 
apparatus from which the air could be exhausted, and for the 
observed lines the following values were obtained : 
At 760™™ and 20° C.._ 1854°09 1862°20 _1935°29 1989-90 
Meevareuuim ©... -- 2. - 1854°77 1862°8L 1935°90 1990°57 
According to Cornu -.- 1852°2 1860°2 1933°5 19881 
The author calls attention to the discrepancy between his results 
and those of Cornu.—Ann. der Physik und Chemie, 1895, No. 5, 
pp. 44—48. Aces 
4. Electrical Resonance.—V. BsERKNxs has collected in a long 
and exhaustive paper the results of his experimental and mathe- 
matical study of the subject ; and he shows that for quantitative 
measurements of electric waves great regard must be paid to the 
following five conditions: (1) The time of vibration of the oscil- 
lator. (2) The time of vibration of theresonator. (3) The logarith- 
mic decrement of the oscillator. (4) The logarithmic decrement of 
the resonator. (5) The constant which measures the intensity of 
the vibrations. He shows that resonance phenomena are in gen- 
eral only suitable for quantitative measures when the mean value 
of the logarithmic decrement of the two conductors is smaller 
than 1. He indicates that quantitative measures with a spark 
micrometer are subject to error and that the electrometer method 
used by him is more suitable for the determination of the above 
five conditions. The student of Hertz effects will find this paper 
the best analysis of the conditions to be observed in performing 
experiments with Hertz apparatus which has appeared.—Anz. 
der Physik und Chemie, No. 5, 1895, pp. 121-169. ah, oh 
II. GkroLogy AND MINERALOGY. 
1. Geological Survey of Michigan; Luctus L. Husparp, State 
Geologist. Vol. V, Part I. Upper Peninsula; Iron and Copper 
Regions. Part Il. Lower Peninsula; Deep Borings. Lansing, 
Mich., 1895. The first part is a Geological Report on the Upper 
Peninsula of Michigan, exhibiting the progress of work from 
1881 to 1884; Iron and Copper regions by C. RomincER, pp. 
1-179, with a map and 2 geol. cross sections. Part II. The 
geology of Lower Michigan with reference to deep borings, 
edited from notes of C. E. Wright, late State Geologist, by 
ALFRED C, Lane, Assistant State Geologist, with an introduction 
on the origin of Salt, Gypsum and Petroleum by Lvctus L. 
HvuBBarD, pp. i-xxiv, 1-100 and plates i-lxxiiii—These reports 
refer to investigations which were made between the years 1881- 
1888 and in part have been referred to in Dr. Wadsworth’s 
