S4 Steam Engine^ 
ture raised by a certain weight of condensed steam. To 
another quantity of water, equal, in weight and temperature 
to that contained in the jar at the outset of the experiment^ 
add a quantity of water at 2^2°, equal in weight to the 
condensed steam j it will be found, on comparison of the 
two resulting temperatures, that a given weight of steam 
has produced, by its condensation, a much greater eleva- 
tion of temperature, than the same quantity of boiling wa~- 
ter. This will be better understood by the following ex- 
ample, taken from actual experiment : 
Into eight ounces of water, at 50® Fahrenheit, contain- 
ed in a glass jar, steam w^as passed from a boiler, till 
the temperature of the W’ater in the jar rose to 173 On 
weighing the water, it was found to have gained 8j 
drachms ; that is, precisely 8 ^ drachms of steam had 
been condensed, and had imparted its heat to the water. ^ 
To facilitate the explanation of this experiment, it is ne- 
cessary to premise the following remarks. 
To measure the whole quantities of caloric contained 
in different bodies, is a problem in chemistry which has 
not yet been solved. But the quantities of caloric, added 
to, or substracted from, different bodies (setting out from 
a given temperature) may, in many cases, be measured 
and compared with considerable accuracy. Thus, if, as 
has been already stated, two pounds of water at 120® be 
mixed with two pounds at 60®, half the excess of caloric 
in the hot water will pass to the colder portion ; that is, | 
the hot w^ter will be cooled 30 , and the cold will re- ^ 
* I find the. following a convenient method of performing this 
experiment. In a tin vessel holding a quart, inclosed in another 
tin vessel and surrounded by an inch of powdered and well dried 
charcoal, put one pint or 16 oz. by weight of water at the common 
temperature of the room. Into a small retort put one ounce of 
water of the same temperature. Evaporate it by a patent lamp, 
placing the end of the retort in the pint of water. When evapo- 
rated try the temperature of the water in the tin vessel. T. C. 
