394 Foreign Literature and Science. 
detail of the proceedings which furnished them, because if, 
on the other hand, we consider them as suflicient to excite 
the interest of chemists in a plant so eminently useful as 
the hop; on the other, the various labors which we: have 
cited, still leave much to be desired. 
34. Electro-Magnetism.—-M. Assiot, Professor of Natural 
Philosophy at Toulouse, states an instance in which, during 
a heavy thunder-storm in that city, on the 22d of June last, 
a metallic tube that extended from the top of the house to 
a well or cistern, served as the channel of a heavy discharge 
of the electric current. The tube was much rent, and oth- 
er damage sustained by the house, which was a small one, 
and contained fourteen or fifteen persons, none of whom 
were injured. The magnetic effects of the stroke were the 
most remarkable. A spike which the fluid met in its way, 
was sufficiently magnetised to lift a table knife, and was 
used in magnetising other things. A tailor’s boy, at the mo- 
ment of the explosion, was smoking his pipe, with the back of 
his chairleaning against a post near the conducting tube ; he 
experienced no disturbance, but was greatly surprised on 
‘the next Monday, in taking his needle-case out of his pock- 
et, to find that the needles were so magnetised that seven 
or eight of them would hang together in a chain. Another 
case, placed on the chimney, twenty feet from the tube, 
and containing five needles, was also strongly magnetised. 
M. Assiot says that he shewed those good tailors who brought 
him their needles, that two or three discharges from a sin- 
gle jar through a wire wrapt spirally round a tube, would 
produce the same effects upon the needles it contained, and 
that evidently without their forming part of the current. 
35. Velocity of Sound.—A very careful experiment was 
made on the 2ist and 22d of June last, at Paris, by order 
of the Board of Longitude, in order to solve this problem 
with greater precision than heretofore. The experiment- 
ers were Humbold,Gay Lussac, Bouvard, Prony,Mathien and 
g 1e former tl tati dth Ivesat Montlhery, 
and the latter three at Ville-Juif, two situations distant from 
9549.6 toises. The experiments were performed in the 
night, by means of two six pounders, one at each station, 
~ 
obese teem 
