380 Scientific Intelligence. 
to satisfy themselves that they are identical. They also examined 
safranine, an orange coloring matter, formed by the oxidation of 
aniline. It isa toluidine derivative, C,,H,,N,, formed by the 
union of three etna i of the monamine, W “ith the substitution 
of one atom of nitrogen for three o ydrogen, and the elimination 
of four atoms of hydrogen.— Ber. Berl. Chem. Ges., v, es, 
1872 
6. Sensibility of the spe te in appa differences in eee 
of different colors—HELM z gives to the Academy of Berlin 
the following ‘analysis of Rew work of W. Dobrowolsky, of St. 
Pete tersburg, on the sensibility of the eye in determining differ- 
ences in intotiett of different colors. If two colors of the same tint 
and of different intensities are placed side b side, the eye ap- 
a their difference in intensity as long as it exceeds a certain 
raction of the intensity of the light observed, as Fechner first made 
known. This fraction for white light " about x$y, and in certain 
Srey favorable cases it equals ;4, or ;¢;- The author 
e researches on different Solow of the solar spectrum, 
with the assistance of two other observers, and gives the following 
figures for the values of the denominator of the fraction. 
First observer. 
Red, A, 14° Blue, Etob, 673 
“ B, 19°76 e F alas 
oe C, 25°16 Indigo, G 268 
Orange, C to D, 33°16 Violet, GtoH 268 
Yellow, D, 45°77 Violet, H 67 
Green, DtoE, 58°77 
Second observer. Third observer. 
B 15°9 
D 40°86 alas 
Between Gand H 205°5 205°5 
The intensity of the violet was not sufficient to give the 
mum sensibilit e see from these results that the sonaibility "of 
the eye in its appreciation of differences in si ncicands ae = ag 
increases as we go from the red to the vio 
; vanie reduction of Iron mig ie influence os a pm 
Sul electro-magnetic solenoid.—J acont, of St. Petersburg, eee 
the interior walls of two glass ei ‘with cylinders of sheet-iron, 
and powed i in these aise = similar s of wax, coated first 
was coiled a helix of insulated copper wir ps 
current from on ll was now passed through the solution 
in the two vessels, w another current from four ne 
