248 Sundry Improvements in Apparatus or Manipulation. 
valve for the admission of water is opened, that for ae it out 
being shut: and less when these circumstances are reversed 
Fig. 2* affords a view of the lower side of the sliding shelf in the 
wood of which it will be seen that there are two excavations, con- 
verging into holes. This shelf is loaded with an ingot of lead at L, 
to prevent it from floating in the water of the cistern. 
_ Culinary Paradox or Ebullition by Cold. 
This figure illustrates a new and instructive method of effecting 
ebullition by cold. 
he apparatus consists principally of a glass matrass, with a neck 
of about three feet in length, tapering to an orifice of about a quarter 
of an inch in diameter. The bulb is bulged inwards, in the part di- 
rectly opposite the neck, so as to create a cavity capable of holding 
any matter which it may be desirable 
to have situated therein. In addition 
to the matrass, a receptacle, holding a 
few pounds of mercury, is requisite. 
The bulb of the matrass being rather 
less than half full of water, and this 
being heated to ebullition, the orifice 
should be closed by the finger, defend- 
ed by a piece of gum-elastic, and de- 
pressed below the surface of the mer- 
cury; the whole being supported as 
represented in the figure. Under these 
circumstances, the mercury rises as the 
temperature of the water declines, in- 
dicating the consequent diminution of 
pressure within the bulb. Meanwhile, 
the decline of pressure lowering the 
boiling point of the water, the ebullition 
continues till the mercury rises in the 
neck nearly to the height of the mer- 
cury in the barometer. 
By introducing into the cup formed by the bulging of the bo 
cold water, alcohol, ether or ice, the refrigeration, the diminution © 
* For this figure see Vol. xiv, p. 200, of this Journal.—Ep. 
