Short Papers and Notes. 67 
of potassium. Peat which has been made to absorb sulphuric, 
nitric, or phosphoric acid, is then also introduced. The acid gra- 
dually acts upon the sulphide and the carbonate, liberating sul- 
phureted hydrogen and carbonic acid in the soil. These two 
gases, according to the experiments of Dr. Eyrich, of Mannheim, 
are rapidly and uniformly distributed, and prove fatal to the Phy/- 
loxera ox grape-vine parasite in its underground stage, as well as 
to Colorado beetles, field mice, moles, etc. The potash remains 
in the soil as a sulphate, nitrate, or phosphate. ‘The question is 
whether useful animals, such as earthworms, humble bees, carni- 
vorous ground beetles, etc., will not be destroyed also. 
Lightning and Barns. 
A writer in the Farmers’ Home Journal says that lightning is 
simply a powerful electric spark caused by a current of electricity 
passing from a positively charged cloud to one that is negatively 
charged. Electricity follows the shortest and most favourable 
course of a good conductor. Water is one of the best conducting 
substances, and a stream or body of heated, moist air affords an 
easy course for the passage of electricity from the clouds to the 
earth. A barn filled with new hay or grain gives off a consider- 
able quantity of moist, heated air, which, rising, forms a column 
often several hundred feet high. ‘This leads the lightning into the 
barn, which, of course, it sets on fire. Barns with ventilating 
cupolas are most often thus burned, by reason of this moist 
current of air ascending in a compact stream. When the ventila- 
tion is through several openings, of course there is less risk. A 
lightning-rod under such circumstances is not capable of conduct- 
ing an electric discharge from the clouds to the ground, and hence 
is no protection, its only efficiency as a safeguard being in 
conducting in one wainterrupted, quiet stream the electric current 
to the ground. Sometimes, it is true, a current of warm, moist 
air, such as in the above case, will conduct the electricity safely to 
the ground, provided nothing should intervene to divert its course, 
but if a break should occur a flash is thus produced, and fire the 
consequence. Stacks of hay for this reason are not so often 
burned as barns. Trees when in foliage continually give off 
moisture through the leaves, and, as a consequence, are often 
struck, while dry, dead leaves as often escape. 
Fluatation. 
Fluatation is the name applied by Messrs. Faure, Kessler, and 
Co., to a new process of hardening building stones through the 
application of hydrofluosilicates. ‘The operation is very simple, 
and can be performed whenever desired, either upon the stone 
before it is put in place, or after the building or other structure is 
