88 
POPULAR SCIENCE REVIEW. 
due in all likelihood to the reprehensible practice of preparing the reduced 
iron from the residues of the preparation of cyanide of potassium from the 
ferrocyanide of potassium. It is therefore advisable for pharmaceutists to 
test the ferrum hydrogenio reduction they purchase for the presence of the 
cyanide alluded to. 
Influence of Heat on Bromine. — Professor Andrews read a paper before 
the British Association on u The Action of Heat on Bromine.” If a fine 
tube, he said, is filled one-half with liquid bromine and one-half with the 
vapour of bromine, and, after being hermetically sealed, is gradually heated 
till the temperature is above the critical point, the whole of the bromine 
becomes quite opaque, and the tube has the aspect of being filled with a 
dark red and opaque resin. A measure of the change of power of trans- 
mitting light in this case may be obtained by varying the proportion of 
liquid and vapour in the tube. Even liquid bromine transmits much] less 
light when heated strongly in an hermetically sealed tube than in its 
ordinary state. 
A Manganese Deposit in a Well. — Dr. Emerson Reynolds submitted to the 
British Association (Edinburgh) the result of an analysis of a singular 
deposit from well water. He stated that in the examination of a sample of 
well water used in mashing paper pulp, in a mill near Dublin, he had found 
that a black deposit formed in the water consisted almost wholly of an oxide 
of manganese. This deposit he found arose from the gradual oxidation of 
manganous carbonate, present in extremely minute proportion in solution in 
the water. 
The Direct Substitution of the Alcohol Radicals for the Hydrogen in Hydric 
Phosphide. — In the “ Berichte derDeutschen Chem. Gesellschaft ” (4ter Jahr- 
gang, p. 205), there is an able account of the above peculiar process. Ab- 
solute alcohol heated with iodide of phosphonium yields hydric phosphide, 
ethylic iodide, and water. Hofmann has employed this reaction in a beau- 
tiful process for obtaining the iodides of triethyl and tetrethyl-phosphonium, 
which consists in simply heating one molecule of iodide of phosphonium 
with three molecules of absolute alcohol in a sealed tube for six to eight 
hours at 180° C. Under these circumstances, the ethylic iodide acts directly 
upon the hydric phosphide to form the iodides of the substituted phospho- 
niums. After cooling, the tube is found filled with a beautiful snow-white 
crystalline mass, which dissolves in water to a perfectly colourless solution. 
The crystals are a mixture of about equal proportions of the iodides of tri- 
ethyl and tetrethyl-phosphonium. A solution of sodic hydrate separates 
triethyl-phosphine as a colourless layer of liquid. The solution then gives, 
on evaporation, beautiful crystals of the iodide of tetrethyl-phosphonium ; 
the triethyl-phosphine, as separated by means of a funnel, is chemically 
pure. The iodides of trimethyl and tetramethyl-phosphonium were easily 
prepared by the same process. In like manner allylic alcohol, phenol, and 
glycerin gave promise of a rich harvest of new results. 
GEOLOGY AND PALAEONTOLOGY. 
What is the cause of Thermal Springs ?■ — This question is asked in a paper 
in the 11 Geological Magazine,” by Mr. Henry Woodward, F.G.S. He thinks 
that water descending to deep levels in the strata meets at some point with 
