650 WONDERS OF ART. 
West Middlesex, at Hammersmitli and Kensington, Ot 
a grand scale, with contrivances for pantying the water; 
and the Grand Junction works, at Paddington. Iron 
pipes have been latterly substituted for wooden ones ; ai'^^ 
tlie general arrangements for the distribution of the wateO 
Hie such as far surpass those of any, similar establisliracnts 
the different capitals of Europe. 
THE DIVING-BELL. 
This invention, by the means of which an operator dc' 
scends to any depth of water, and remains there for several 
hours, is founded on the elasticity of the air. Weights are 
placed at the bottom to prevent it from turning ; and a 
forcing-pipe sends in fresh air, to supply the waste of vital 
air from the respiration of the operator. 
The sinking and raising of the diving-bell, invented bY 
Br. Halley, depending entirely on the people at the surface 
of the water, and being besides of considerable weight, a® 
as to occasion much labour, with a risk of the breaking 
the rope by which it was to be raised, to the sure destroC' 
tion of those within, a diving-bell has been invented bY 
Mr . Spalding, of Edinburgh, to remedy these defects, and 
prevent the edges of the machine from being entangled bJ 
any ragged prominences of rock. His machine is of wood, 
suspended by ropes, and having leaden weights appended to 
it, by which the mouth of the bell is kept always parallel 
to the surface of tlie water, whether the machine, take* 
altogether, is lighter or heavier than an equal bulk of water 
By Uiese weights alone, however, the bell would not sink! 
another is therefore added, which can be lowered or raised 
at pleasure, by means of a rope passing over a pulley, *r>d 
fastened to one of the sides of tlie bell. As die bell de- 
scends, this weight, called by Mr. Spalding the balance- 
weight, hangs down a considerable way below the mou'b 
of the bell. In case the edge of the bell is caught by 
obstacle, the balance- weight is immediately lowered doWf' 
so that it may rest upon the bottom. By this means ban 
bell is lightened, so diat all danger of oversetting is 
moved ; for being lighter, without the balance- weight, tliao 
an equal bulk of water, it is evident that the bell will rise as 
far as the length of the rope affixed to the balance-weig** 
will allow it. This weight, therefore, serves as a kind o 
