96 
the hydrogen passed off 120 times as fast as at the tempera- 
ture of 60°. Also when the saturated iron was plunged into 
warm water the gas passed off as if the iron had been 
plunged into strong acid ; so that we can easily understand 
how the hydrogen would pass off from the wire quickly 
when warm, although it would take long to do so at the 
ordinary temperatures. With regard to the frothing of the 
wure when broken and wetted — this was not due, as at first 
sight it appeared to be, simply to the exposure of the inte- 
rior of the wire, but was due to warmth caused in the wire 
by the act of breaking. This was proved by the fact that 
the froth appeared on the sides of the wire in the imme- 
diate neighbourhood of the fracture, when these were 
wetted, as well as the end ; and by simply bending the wire 
it could be made to froth at the point where it was bent. 
As to the effect on the nature and strength of the iron I 
cannot add anything to what Mr. Johnson has already 
observed. The question, however, appears to be one of very 
considerable importance, both philosophically and in con- 
nection with the use of iron in the construction of ships 
and boilers. If, as is probable, the saturation of iron with 
hydrogen takes place whenever oxidation goes on in water, 
then the iron of boilers and ships may at times be changed 
in character and rendered brittle in the same manner as 
Mr. Johnson’s wire, and this, whether it can be prevented 
or not, is at least an important point to know, and would 
repay a further investigation of the subject. 
Dr. Eansome, M.A., demonstrated the movements of the 
chest in respiration, showing the remarkable mobility of its 
several parts, and the consequent facility with which its 
cavity can be infiated. 
Its motions are conditioned by the shape and mode of 
articulation and degree of movement of the bones composing 
it. 
