8 British Association for the Advancement of Science. 
instantly set about drawing up their boats and placing their ‘small 
craft in more secure places ; early the next morning a violent storm 
came on, which did much damage upon the coast, to those who 
had not been similarly forewarned. It might perhaps be accounted 
for by supposing that on these occasions the intervening air be- 
came actually converted into a large magnifying lens. 
Magnetie Intensity.—Determinations of the value of the ter- 
restrial intensity have been obtained at between forty and fifty 
widely scattered stations, principally in the southern hemisphere, 
where such determinations had been previously a great desider- 
atum. 
The iuatabot of separate Seteroaidurioas collected in this Report 
exceeds six hundred, and the number of stations falls a little short 
of five hundred. ‘They are the work of twenty-one observers, 
and of these the observations of seven have been hitherto unpub- 
lished. 
Beer.—Mr. Black communicated a paper ‘ On the Influence of 
Electricity on the processes of Brewing.’ According to his state- 
ments, a thunder-storm not only checks the fermentation of worts, 
but even raises the gravity of the saccharine fluid, and developes 
in itan acid. This effect is witnessed principally when the fer- 
menting tun is sunk in moist earth, and may be obviated by pla- 
cing it upon baked wooden bearers, resting upon dry bricks or 
wooden piers, so as to effect its insulation. Mr. Black also stated, 
that during the prevalence of highly-electrified clouds, the fabri- 
cation of cast iron does not succeed so well as in other states of 
the atmosphere. 
Electrical Relations. —Dr. Faraday cautioned chemists against 
considering electrical relations as affording, in every instance, con- 
clusive proofs of what is a base and what is an acid. 
Electrical Protection.—A \etter was next read, addressed by 
Mr. Locke to Mr. W. W. Currie, of Liverpool, in which the latter 
was requested to propose as a question, to the philosophers assem- 
bled, whether, in the case of a monument one hundred and forty 
feet in height, erected on the summit of a mountain fourteen hun- 
dred feet high, augmented safety or danger would be the conse- 
quence of attaching to it a conductor or paratonnerre. "The col- 
umn is sandstone, the mountain conglomerate, and in the vicinity 
of the latter there is a mountain of still greater elevation. It was 
resolved, that this letter should be, pro formé, i Se hands 
