AS A SUBSTITUTE FOR FIRE ENGINES. 
137 
pumper. The weight of the column of 
water in the main, which kept augmenting 
only until it reached a point now to be 
noticed, was adding continually its pressure to 
the weight of atomosphere, by which the 
delivery was accelerated by the cocks upon 
the lateral branch, turned on till it attained 
a point of equilibrium- — a point at which 
the cock upon the lateral branch, although 
of less diameter than the main, or the barrel 
of the pump, delivered water just as fast 
the pump could raise it. 
When all the cocks upon the lateral 
branches were turned off, the discharge up at 
the chimney, at the top of the main, was so 
profuse and forcible, that it led me to expect 
that, if a pump of this description were fixed 
in every house, and a flexible or hose pipe 
fitted by an union joint to the end of the 
main, or at some more convenient part, it 
might, in the case of fire in the establish- 
ment, be of considerable use as a fixed 
fire-engine, as well as serve the purposes of 
an ordinary pump for domestic uses. 
Ka-ppa. 
.Sept. 21, 1835. 
ELECTRO-MAGNETIC MOVING 
POWER. 
that the model would continue working. 
The acid best suited to the purpose was a 
mixture of one part nitric acid, two parts 
sulphuric, and one hundred water ; he also 
stated that the acid in practice could be 
always renewed by having a constant drop- 
ping of fresh acid liquor into the trough, 
while a similiarly gentle discharge of the 
spent acid from the trough could be kept up. 
He stated, that a numerical comparison of 
the economy of this mode of producing 
motive power with that depending upon the 
agency of steam, would give a vast prepon- 
derance in favour of this method, w^hile the 
part of the power’ consumed in w^orking the 
machine itself might be left entirely out of 
account, since the apparatus which changed 
the poles in his model, would equally suffice 
in a machine capable of working with the 
power of one hundred horses. In his model 
he only worked one of the two soft iron 
magnets, and its power was only that of 
lifting seven pounds, and yet this appeared to 
be sufficient to overcome all the friction, 
inertia, and other impediments to motion, of 
the several parts of the machine. 
The exhibition of this model was received 
with sincere and reiterated applause, and 
many scientific men present expressed san- 
guine cxpeetations of the value of the method 
in a practical point of view, all agreeing that 
it was the best attempt yet made of the many 
schemes that had been proposed for produc- 
ing motive power by the electro-magnet. — 
Athencewm. 
British Association, — Section of Mathematics 
and General Physics. 
The Rev. Mr. M’Gauleyexhibited the work- 
ing model of a machine for producing moving 
power by the application of electro-magnetic 
influence. The model consisted of a pendulum, 
the lower part of which was a magnet placed 
with its poles opposite to the ends of two 
horse-shoe bars of soft iron, round which 
were coiled helices of wire so arranged that 
by the end of the helices dipping into cups of 
mercury the poles of a simple galvanic battery 
could be alternately made to communicate 
with the cups in one order, and the next 
instant the machine reversed that order by 
means of a system of bent wires, caused to 
vibrate upon an axis, the ends of these bent 
wires alternately dipping into one pair of cups, 
and the next vibration into another; by these 
means the soft iron horse-shoes are at one in- 
stant a magnet’with the poles in one order, the 
pendulum being then attracted towards both 
these poles, but the next instant, the poles 
being reversed, the pendulum is thrown for- 
cibly back, while the opposite soft iron horse- 
shoe is now a magnet ready to attract it ; 
then again it is thrown back from this second 
temporary^ magnet by the instantaneous 
reversing of its poles, and so on. The model 
worked smoothly and with a very uniform 
regulated motion, and appeared to be capa- 
ble of working for a great lenth of time. 
Mr. M’Gauley stated that the erosion of the 
zine plate was so inconsiderable, that there 
•v\ras hardly any limit to the length of time 
PAINTED BINDING.— Many beautiful 
subj ects may be formed on the sides of books by 
the workman skilled in painting. The volume 
is prepared by being pastewashed, so as to 
present an uniform fawn colour, the desings 
slightly traced, and afterwards coloured accord- 
ing to the pattern, the colours being mixed to 
the proper shade with water. The shades 
must be tried on pieces of refuse leather, as, 
being spirit colours, when once laid on, no art 
can soften them down if too strong ; and a 
peculiar lightness of touch will be necessary 
to produce eftect. Portraits, &c., may also 
be executed in this manner ; and many superb 
desings have at times been executed by 
the best binders of this country and France. 
M. Didot, booksellers, of Paris, presented 
a copy of the “ Henriade,” published by him- 
self, to Louis XVIII., most elegantly orna- 
mented in this style. It was executed by Mr, 
Bellier bookbinder, of Tours, and presented 
on one side a miniature portraite of Henry IV. 
and on the a similar one of Louis XVIII. , both 
perfect likenesses. The greatest difficulty con- 
sisted in the portraits, which were first 
imprinted on paper, very moist, and immediatly 
applied to the cover, on which they were 
impressed with a fiat roller. When perfectly 
dry, they were coloured with all the art of 
which the binder was capable, and the other 
ornamental paintings executed by hand. This 
proceeding requires great care in the execu- 
tion ; and will be applicable to any design 
where the binding will justify the expense. — 
ArnetVs Bihliopeyia. 
