82 Intelligence and Miscellaneous Articles. 
of 0°2 grain of copper and a surplus of O°1 grain of oxide of nickel ; 
errors so small that they are evidently those of manipulation and not 
owing to any defect in the process followed. 
70 grains of German silver gave by the above process : 
Goppersros sees a. saa 
DIMER TUG Lo stelle s cls PD 
Nickelig? 35 B28 /s.92 thee, Sse 
Gobaltht, cae. Sudeep f.9 234 
70:2 
There appears to be a larger proportion of copper in this than is 
generally met with in German silver, for only one out of four alloys, 
the composition of which, on the authority of Gersdorff, is given by 
Bourchardat (Cours de Chimie, 1* partie, page 289), contains as 
large a proportion of copper as the specimen | analysed, and to it 
may be attributed the very yellow shade which this alloy possessed ; 
its chief advantage over many others being what is technically called 
* dipping well.’ 
The same method may doubtless also be employed to separate 
manganese and cobalt from zinc, for solutions of the former metals, 
when acidified by acetic acid, are not precipitated by sulphuretted 
hydrogen gas. 
St. Thomas’s Hospital, 
December 1835. 
ACTION OF MUSHROOMS ON ATMOSPHERIC AIR. 
M. Marcet subjected known quantities of mushrooms to the action 
of oxygen, azote, and atmospheric air under graduated receivers; and 
having left them for a certain time, and ascertained the alteration 
both in the volume and nature of the gases; the conclusions at 
which he arrived, after performing numerous experiments, are the 
following: 
Ist. That mushrooms produce very different effects upon atmo- 
spheric air from those which result from the action of green plants 
under similar circumstances. They vitiate the air very readily, either 
by absorbing its oxygen to form carbonic acid gas at the expense of 
the carbon of the vegetable, or by disengaging carbonic acid ready 
formed. 
2nd. That the modifications which atmospheric air suffers by the 
contact of mushrooms in a vegetating state are the same day and 
night. 
3rd. That if fresh mushrooms are suffered to remain in pure oxygen 
gas, a large portion of the gas disappears in a few hours. One part 
of it combines with the carbon of the vegetable to form carbonic acid 
gas, while another portion is fixed in the vegetable, and is replaced 
by azotic gas liberated from the mushrooms. 
4th. That fresh mushrooms, by remaining for some hours in azotic 
gas, produce but little change in it ; a small quantity of carbonic acid 
