Chemistry and Physves. 419 
interval of twenty-five years during which: Dr. Hunt was one of 
the persecutors if there were any such—an interval, moreover, 
_ which was continued, without any abatement in the opposition on 
Dr. Hunt’s part, for twelve years after Professor Kmmons’s 
decease. 
I think I have stated facts enough to end the Taconic contro- 
versy. The work which Professor Emmons did in the strati- 
graphical geology of the Taconic region and his discoveries in 
Paleontology will in the main stand; while no effort can keep 
life in wrong conclusions, whatever the source. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHYSICS. 
1. On the generation of Chlorine gas in Kipp’s apparatus.— 
The'use of bromine in the laboratory would appear to be due in 
many cases to the inconveniences attending the ready preparation 
of the more active chlorine. WINKLER has sought to render the 
preparation of chlorine easier by suitably modifying the ordinary 
process of obtaining this gas from chloride of lime and hydro- 
chloric acid. For this purpose the chloride of lime is mixed with 
about a fourth of its weight of calcined gypsum, and then so 
moistened with cold water as to form a crumbly semi-coherent 
mass. It is stirred in a mortar until entirely homogeneous and 
then is beaten with an iron mallet into a square iron frame ten or 
twelve millimeters thick, resting on an iron plate. When full the 
sides are covered with wax-cloth and the whole is submitted to 
the action ofa strong press. The square cake thus obtained is then 
cut into smaller squares and dried at a temperature not exceeding 
* 20°. The cubes thus obtained should be preserved in a well- 
closed vessel. When used they are placed in a well-made Kipp’s 
gas-evolution apparatus, with hydrochloric acid of 1:124 specific 
gravity previously diluted with an equal volume of water. The 
preparation of chlorine in this way is as convenient and its evolu- 
tion as constant as that of carbon dioxide by the use of marble. 
The author announces that Trommsdorff has agreed to keep these 
cubes already made, on hand for sale-—Ber. Berl. Chem. Ges., 
xx, 184-5, Feb. 1887. G. F. B. 
2. On the action of Kaolin on the alkali-chlorides.—In study- 
ing the action of kaolin on the halogen compounds of the alka- 
hes, Gorcru has shown that when this substance is calcined 
with these compounds, double neutral silicates are formed, which 
themselves in some cases form direct combinations with the halo- 
gen salts. The sodium-aluminum silicate thus formed unites 
directly with soium iodide to form a well crystallized compound. 
When the kaolin is calcined with sodium or potassium chloride, 
