SCIENTIFIC SUMMAKY. 
305 
of tlie imperial green removes all danger from insalubrity ; it is an impal- 
pable substance, of perfect tenuity. It is believed that this property will 
cause the new green to be adopted for printing on stuffs, and for other pur- 
poses. The oxides of chrome known up to the present time, and generally 
obtained in the dry way, cannot, by pulverisation, attain to the degree of 
fineness of the imperial green. It is expected that this substance will have 
great success in oil painting, coloured papers and artificial flowers, printing, 
lithography, perfumery, and soap manufacture, as well as in the making 
of glass and in the ceramic arts. — Vide Artizan, April. 
Death of M. Nikles. — M. Nikles, who held the chair of Chemistry in the 
Faculty of Sciences at Nancy, has died during the past quarter. He had 
reached the age only of forty-nine years. His disease was an affection of 
the lungs, brought on by some researches in fluorine compounds. 
Decompositioti of tliQ Sesqui-mlts of Iron. — At the meeting of the French 
Academy on the I9th of April, a memoir was presented from M. Debray. 
^‘When,” says the author, ‘‘we heat a solution of neutral chloride of sesqui- 
oxide of iron, so dilute that its colour is hardly perceptible, when it reaches 
to above 70° Cent, it becomes decidedly coloured, and assumes the charac- 
teristic tint of the basic chlorides of the sesquioxide. This transformation 
is not due to the disengagement of hydrochloric acid, since the transforma- 
tion can be effected in closed vessels, and the colour is maintained on cooling. 
The chemical properties of the iron salt are profoundly modified ; thus, 
whilst the primitive liquor gives with the yellow prussiate of potash an 
intense precipitate of prussian blue, the coloured solution gives with this 
reagent but a pale greenish blue precipitate ; also sea-salt, which has no 
action in the colourless solution, gives with the modified chloride a gela- 
tinous precipitate of hydrated sesquioxide of iron.” The author concluded 
by expressing the hypothesis that the iron is reduced by the temperature to 
a colloidal condition, which is kept in solution either in hydrochloric acid or 
in sesquichloride of iron. 
Artificial Dreparation of Alizarin. — At a recent meeting of the Literary 
and Philosophical Society of Manchester, Professor Roscoe described the 
discovery, , by MM. Graebe and Liebermann, of the artificial preparation of 
alizarin, the colouring matter of madder, from anthracene or hydrocarbon 
found in coal tar. It appears that the formula given for alizarin many 
years ago by Dr. Schuuck — viz., H^^^ 0^, corresponds closely to the com- 
position which the substance is now found to possess — viz., Cj^IIg 0^. We 
are as yet unaware how alizarin is obtained from anthracene Cj^ H^^. The 
artificial colouring matter appears to possess all the properties of the madder 
alizarin, and the ordinary mordants yield the well-known colours in every 
respect identical with those obtained in the well-known processes of 
madder-dyeing. The importance of this discovery can hardly be over- 
estimated. 
The Chemistry Professorship of Ddinhurgh University. — Dr. Crum Brown 
has been appointed Professor of Chemistry in Edinburgh University. 
Modus Operandi of Creosote. — Mr. P. Moir, in the Glasgow Philosophical 
Society Reports, thus expresses the properties of this substance as a pre- 
servative : — “I. It coagulates albuminous substances and gives stability to 
the constituents of the cambium and cellulose of the young wood. 2. It 
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