42 



ELEMENTS OF LABORATORY WORK 



A given substance may be conveniently raised to a high 

 temperature, and transferred to the known quantity of water 

 with less risk of its temperature falling during the transfer, if, 

 instead of the last process, we use a wide tube A (fig. 1 3), fitted 

 at each end with a cork, through which an inner tube B passes. 



Fig. 13. 



The space between the two tubes is now filled with steam by 

 connecting it at s with a flask of boiling water ; a cork, into 

 which a thermometer c is fitted, serves to hold the body sus- 

 pended in the inner tube, and to allow it to fall, when required, 

 into the water, which should be placed directly underneath. 



We learn from the table below that a given change of 

 temperature in 1 gram of water is equivalent to the same 

 change of temperature in 1'62 grams of ethyl alcohol, 2 -2 2 

 of benzene, 10*64 of brass, and so on. These values will be 

 found to bear no relation to densities or to the quantities of 

 matter in equal volumes of the various bodies. They indicate 

 a totally distinct relationship between various kinds of matter, 

 and later observations in electricity and chemistry will show 

 that this relationship may be discovered in other phenomena. 



