: Proceedings of the British Association. 43 
moment when it is neither increasing nor diminishing in tempe- 
rature, which will be a little before sunrise. If this is a true ex- 
planation of the four fluctuations of the barometer ina day, it 
will follow that the morning rise ought to be greater at consider- 
able clowhions, provided they are not too great, because some of 
the air will be lifted above the place of observation ; and such 
was found to be the case by Col. Sykes in India. As this morn- 
ing rise of the barometer depends on the increasing elasticity of 
the air, and this increasing elasticity, on heat, Mr. E. proposed to 
the mathematicians to calculate how much the whole atmosphere 
is heated from sunrise till the time when the barometer stands 
highest, the actual rise of the barometer being given. In this 
way meteorology may assist astronomy. Prof. Forbes doubted 
the correctness of Mr. E.’s views of the great daily fluctuations 
of the barometer at elevated stations: for, towards 2 or 3 o’clock 
the heat being greatest, its effect in lifting up the inferior air to 
and above the elevated station, should then be greatest, whereas 
that time of the day was nearer to the time of minimum height 
of the barometer than of itsmaximum. After the announcement 
of the titles of a few other papers, the business of the Section was 
concluded. 
Sect. B. Chemistry and Mineralogy. 
A paper on some electrical phenomena, and on a supposed new 
substance, was presented by Dr. Schénbein. It is well known 
to electricians that in certain electro-chemical decompositions a 
peculiar odor is evolved, very analogous to that produced by com- 
mon electric sparks, or by the working of an ordinary electrical 
machine in the air. Dr. 8. has undertaken a series of experi- 
ments in order to ascertain the circumstances under which this 
electro-chemical odor is evolved, the causes which influence its 
production, and if possible, the principle to which its appearance 
is to be attributed. This peculiar odor is evolved at the anode 
or positive surface, when certain aqueous solutions are decompo- 
sed by the passage of a voltaic current. The oxygen gas which 
is then evolved has a strong and peculiar smell, which is perfectly 
similar to that which is always perceived when an electrical ma- 
chine is worked or sparks passed through the air. M. Schénbein 
has: observed that the odor is evolved on the decomposition of 
water, dilute sulphuric acid, solutions of phosphoric and nitric 
er 
