SCIENTIFIC SUMMARY. 
419 
of change to single flowers. The plant was quite attractive; and as it 
blooms very early and profusely, it would seem to have some of the 
qualities required to entitle it to a place among cultivated flowers. 
CHEMISTRY. 
Detection of Nitrogenised Matter in the Atmosphere. — Mr. A. H. Smee has 
described (“ Chemical News,” July 19) a method which he has devised, 
and which he names “ distillation by cold,” by which he believes the de- 
tection and determination of ammonia and other organic impurities existing 
in the atmosphere will be greatly facilitated. A glass funnel (usually of 
8 or 9 inches) is drawn to a point and closed. It is supported in an ordinary 
stand, and filled with ice. Condensation of the watery vapour of the at- 
mosphere then takes place ; the dew collects into drops, which trickle down 
the outside of the funnel, and at last fall from the point, under which a 
small receiver is placed to catch them. The total quantity of liquid collected 
in a given time is measured, and the quantity of ammonia determined by 
Nessler’s test. By the method of distillation by cold, the author found it 
possible to distil many substances which are decomposed at a high tempe- 
rature. Thus many delicate odours of flowers were distilled by placing the 
flowers under a bell-glass sufficiently large to cover the funnel containing 
the ice. The odours were found to be more rapidly and completely ab- 
stracted by placing a dish with a little ether under the bell-glass at the 
time of distillation. The paper was accompanied by tables giving the 
results obtained in 107 experiments, together with the atmospheric condi- 
tions prevailing at the time. The experiments were made in a garden, in 
a bed-room, in hospital wards, in the open country, &c. 
A Method of obtaining Potassium. — Professor A. Dolbear has described 
the following mode : — Some white stick caustic potash of commerce is dis- 
solved in water and then treated with sulphuretted hydrogen in the way 
commonly described for making potassium sulphide, K 2 S. The solution is 
evaporated until it is solid when cool, when the yellowish mass is mixed 
with more than its bulk of iron filings and chips, and the whole put into an 
alembic for distillation. The heat of a furnace is applied till the alembic is 
of a bright red heat, and the products of distillation are received in com- 
mon coal oil. The product is rather small, as some of the potassium vapour 
decomposes the heated vessel ; nevertheless the potassium shows itself when . 
the oil is poured offj and the residuum turned upon water, by its character- 
istic ignition and flame. The reaction is simple, and may be thus repre- 
sented. K 2 8 + Fe = FeS + K 2 . 
Chemical Action during a number of Years. — In the (i Comptes Rendus,” 
July 8, M. Becquerel has a paper which contains the account of the results 
of some experiments which prove that, by slow but continued action, curious 
effects may be obtained ; for instance : Crystals of arragonite are formed 
upon a piece of gypsum (lance-shaped variety) kept in a closed vessel in a 
solution of bicarbonate of potassa ; the gypsum has almost entirely dis- 
appeared, having become converted into arragonite. A similar piece of 
e e 2 
