ON WATER-PRESSURE ENGINES. 1l 
could not say which, they vanished so rapidly. It appeared a few degrees 
below the Pole-star, or a little to the eastward, and descending towards the 
____ western horizon, /z¢ the lowest of the Pointers, and disappeared a few degrees 
_ beyond it.” 
70. In this communication (to M. Quetelet) the author remarks that the 
__  Zenithal line parallel to which the greatest number of meteors were directed, 
_ was from N.N.E. to S.S.W. nearly as observed in the previous year, [at Ply- 
mouth]. Others passed to the northward, and on combining the whole it 
resulted as a general view, that the movements appeared to originate about a 
point N.E. of the zenith, near Cassiopeia, and that the meteors passing south- 
_ ward were more numerous than those proceeding to the north.”—Bull. de 
_LAc. Roy. de Bruxelles, 1842, p. 324-326. 
On Water-pressure Engines. 
By Josepu Guynn, F.R.S., M. Inst. C.E. &c. 
(A communication ordered to be printed entire among the Reports to the Association.) 
Ar the last meeting of the British Association in Oxford, I read a report on 
the Turbine as a means of obtaining mechanical power, with a rotary motion 
from falls of water in circumstances where a water-wheel could not be em- 
ployed. The report I propose to submit to the present meeting relates to 
another mode of employing the power of waterfalls in a manner essentially 
different, but not less useful and important, which appears to have been too 
much neglected in this country, considering the advantages to be derived 
from it in hilly districts for the drainage of mines. The paper on the Tur- 
_ bine is printed in the last volume of the Transactions; the present paper, 
_ which may be regarded as another branch of the same subject, describes the 
_ application of high falls of water to produce a reciprocating motion by means 
of the pressure-engine, as has before been done with respect to the produc- 
tion of a rotary motion by means of the Turbine. 
The first invention of the water-pressure engine, like many other mecha- 
nical contrivances, appears to belong to Germany, and most probably had its 
origin in Hungary, where so many ingenious machines actuated by water 
_ have long been used. In the pressure-engine the power is obtained from a 
descending column of water acting by its weight or hydrostatic pressure 
upon the piston of a cylinder, to give motion to pumps for raising water to 
a different level, or to produce a reciprocating motion for other purposes. 
In mountainous districts, so often containing great mineral wealth, water- 
falls may be found of a much greater height than can be practically brought 
_ to bear upon water-wheels; and the stream is often too small in quantity to 
produce the desired effect on a water-wheel within the ordinary limits of 
_ diameter. In such situations the pressure-engine is well-adapted to derive 
great mechanical power from a fall of water for working pumps and ma- 
chinery for draining mines. 
_ The Germans appear to have made successive improvements upon their 
original engines, and to have extended, from time to time, their usefulness 
and application, of which two important examples may be given. 
_ The one is at Illsang in Bavaria, at the salt-works, which are situated in 
_ the southern part of the kingdom. These works are supplied from a mine of 
rock-salt in the valley of Bergtesgaden and from the salt springs at Reichen- 
hall, where the salt was formerly purified by solution and evaporation; but 
_as this operation could not be carried on with advantage on account of the 
_ scarcity of fuel, the saturated brine is now conveyed by a line of pipes seven . 
inches in diameter, through which it is forced from stage to stage for a 
