Chemistry and Physves. 151 
portions, the green fluorescence of the calcium salt predominated 
when the weights of the two sulphates (zinc and calcium) were 
equal; while with equivalent weights the red of the zine salt was 
slightly the stronger. This result increased with the proportion 
of the zinc sulphate until it became 98 per cent, the fluorescence 
being orange-red. On interrupting the current, the orange fluores- 
cence quickly disappears, while the green of the calcium sulphate 
remains for a considerable time. 
The author has also ascertained that calcined alumina does not 
give a trace of fluorescence when submitted to the electric dis- 
charge in vacuo. The characteristic fluorescence of this substance 
as described by Becquerel, who has figured its spectrum, is most 
brilliant when the alumina contains one per cent or even one-tenth 
of one per cent of chromic oxide. A very perceptible rose color 
is given by one hundred thousandth of chromic oxide. One per 
cent of manganous oxide yields a beautiful green, and the same 
quantity of bismuth oxide a lilac when cold and a blue on heating. 
Magnesia with one per cent of chromic oxide gives a fine red 
color; while lime does not appear to be affected by this oxide. 
The red fluorescence of alumina seems then to depend upon the 
presence of chromium; the analogy being complete between its 
action and that of manganese, bismuth, Za, Z(6 and samarium.— 
C. F., cili, 468-471 (Sept.) ; 629-631 (Oct.); 1064-1067 (Nov.) ; 
1107 (Dec.), 1886. G. F. B. 
5. On the Refractive index of Carbon dioxide and of Cyano- 
gen.—Cuappuis and Riviere have deduced from their researches 
upon carbon dioxide at 21° and under pressures up to 19 atmos- 
pheres, and upon cyanogen at temperatures from 0° to 35° and 
pressures from 1 to 3 meters of mercury, formulas for calculating 
their refractive indices. ‘They find for carbon dioxide at 0° and 
0°76 meter, the value 1000448, and for cyanogen under the same 
conditions 1:000825.—C. &., ciii, 37-39, July, 1886. G. F. B. 
6. The Spectrum of Germanium. — This spectrum has been 
mapped by H. Gustaf Kobb. It was formed by passing sparks 
from a large induction coil from an electrode of germanium to one 
of platinum. The lines of the latter could be readily identified 
a separated. The germanium lines are given in the following 
table : 
i OBSERVATIONS. > 
6336 5131 Broadly diffused. 
6020 Very strong. 4813 # oe 
5892 o 4742 i ns 
5255°5 4684°5 Sharp, weak. 
5228°5 4291 Diffused weak. 
5209 4260°5 sf ‘ 
51775 Broadly diffused. 4225°5 
5134 4178 et af 
Ann. der Physik und Chemie, No. 12, 1886, p. 670. seers 
kb 
i. A new Quicksilver Pump.—The three different systems of 
quicksilver pumps—the Geissler, the Tépler and the Sprengel— 
have their peculiar advantages and disadvantages. The Geissler 
Au. Jour. Sci.—Tuirp Series, Vou. XX XIII, No. 194.—FEBRUARY, 1887. 
10 
