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colourless. As the author states that the crystals may he obtained very 
pure, even from solutions containing sulphate and chloride of sodium, it 
seems probable that they will afford a ready means of obtaining pure soda 
for laboratory purposes. The formula of the crystallized hydrate is Na 0, 
-f 8 H O ; by long standing over sulphuric acid the compound loses four 
equivalents of water. Rose, who examined the crystals, found them to be 
oblique rhombic. — Vide Poggendorff’s Annalen , cxix., and Sillimarfs Ameri- 
can Journal , 1864, No. 109. 
A non-arsenical green Colouring Matter has been discovered by Dr. 
Eisner in a very accidental way. He was requested to analyse a quantity 
of green powder, which was termed green cinnabar, and during the opera- 
tions to which he submitted it he observed that the compound was hot 
arsenical, but was composed of various proportions of prussian-blue and 
chromium green. He found that it possessed every possible degree of 
shade between the two tints. This colouring matter is well adapted to the 
manufacture of paper hangings, but cannot be used for walls on account of 
the prussian-blue, which would undergo change ; neither can it be used 
in colouring bon-bons, because of its injurious qualities. The following 
is the recipe for its preparation : Make a solution of yellow chromate 
of potash, and another of yellow prussiate of potash, and then mix the two. 
Dissolve separately, in water, some acetate of lead and iron, and add this 
solution to the others. In this way a precipitate will be obtained, whose 
tint will depend on the proportions of the ingredients employed ; of course 
the larger the quantity of acetate of lead and chromate of potash, the 
lighter will the colour produced be. The precipitate should be carefully 
washed, and dried at a gentle heat. — Vide Moniteur Scientifique i v., 882. 
Composition of the Harrogate Waters. — It appears from a communica- 
tion of Dr. S. Muspratt’s that the springs of Harrogate, which have been 
lately so much resorted to by persons suffering from cutaneous diseases, 
have the following composition : In an imperial gallon there are 41*626 
grains of mineral matter, which is thus composed : Carbonate of lime, 
10*498 grains, carbonate of magnesia, 1*002, carbonate of soda, 15*093, 
sulphide of sodium, 2*852, sulphate of magnesia, 4*593, chloride of 
magnesium, 5*741, chloride of sodium, 1*006, silica, 0*841, traces of car- 
bonates of iron, potass, and manganese, and also of ammonia and chloride 
of potassium. Dr. Muspratt thinks that Dr. Hoffmann’s assertion, that 
part of the sulphuretted hydrogen of these waters is in the free state, is 
open to considerable doubt. — Vide The Chemical News , No. 228. 
Chemical Professorships. — In accordance with the suggestions of the 
Commissioners, the Royal Academy of Arts has determined to found a 
chair of Chemistry. We learn also upon excellent authority that the 
chair in Berlin, held by the late Professor Rose, has been offered to and 
accepted by Professor II. Kopp, of Giessen, who will soon enter upon the 
duties of his new office. Dr. Hoffmann’s refusal of Rose’s chair resulted 
from his having been offered a very large sum by the Bonn authorities 
for the construction of a new institute of Chemistry, over which he is 
expected to preside. 
Chloi'o-carbonic Acid is said by Dr. Schiel to be formed when a 
perfectly dry mixture of chlorine and carbonic acid is passed through a 
