320 Scientific Intelligence. 
After washing, the double filter is placed in an air-bath heated 
to about 120° C., and in about 30 minutes weighted by sep- 
arating the filters, the complete dryness is verified by a second 
heating in the air bath. 
Of the phospho-molybdate every 100 m. g. will contain 
1°63 m. g. of phosphorus, or 3°74 m. g. of phosphoric acid. The 
result of this method of analysis will indicate a very minute 
quantity of phosphorus less than what is contained in the iron, 
ut so small as not to affect the practical result, and will be 
more accurate, certain and speedy than if estimated as magne- 
sian phosphate. 
Cold short iron.—It has been customary to attribute the cold 
shortness of certain iron to the presence of phosphorus. Now, 
after working on this problem in rolling mills, I have found 
that the phosphorus cannot alone account for this peculiarity. 
Very often I have taken a 1-inch and 13-inch iron that was very 
cold short and working them down to smaller sizes, as }-inch 
bars, etc., found that very good merchantable iron is produced, 
capable of being bent and forged cold or hot as well as any 
good quality of iron, although the phosphorus in the large 
and small iron is the same in quantity. I would not say that 
phosphorus has no effect on the cold shortness of iron, but I 
would remark that whatever effect it has is very much modi- 
fied by the manner of working the iron. And this opinion is 
sustained by that of others who have had much to do with the 
working of iron. 
SCIENTIFIC INTELLIGENCE. 
I. CHEMISTRY AND PHysICcs. 
1. Apparatus for illustrating the action of Geysers.—In J. 
Miiller’s Cosmical Physics, 2d ed., p. 386, 1865, Bunsen’s theory 
of the eruption of geysers is illustrated by filling a vertical me- 
tallic pipe with water and applying heat to its middle portion 
and to its lower end. G. Wiedemann believes that this appara- 
tus does not truly represent the actual phenomenon, since It 1s 
hard to conceive of the earth’s heat being applied in two points ; 
and he has for-several years used the following apparatus in his 
lectures. A Florence flask is provided with a long vertical glass 
tube drawn out at its upper end into a comparatively small orifice. 
Another glass tube passes through the cork which closes the mouth 
of the flask and is led away at an angle to a glass bottle which it 
enters by a stop cock at the base of this bottle. This bottle is filled 
with water, the height of the liquid being about at the level of 
the top of the vertical glass tube which rises from the Florence 
