90 Domestic Science 



apparent loss of weight of the solid body. If the 

 experiment has been carefully performed, these quanti- 

 ties should be equal. 



The result of this experiment is put into the form 

 of a general statement as follows : 



The apparent loss of weight suffered by a body as 

 the result of immersion in a liquid is equal to the 

 weight of the liquid displaced by the immersed body. 



The above statement is known as the " Principle 

 of Archimedes ", having been first enunciated by that 

 philosopher. 



Exercise for Student. 



In the above experiment water was the liquid used. Devise 

 and carry out another experiment whereby the validity of the 

 Principle of Archimedes may be tested in the case of some other 

 liquid, e.g. methylated spirit. 



53. The above-named principle is of great service 

 in making determinations of the value of many quanti- 

 ties which are not readily found with accuracy by other 

 means. The volume and specific gravity of an irregular 

 solid body may be found as shown in 



EXPERIMENT 29. Find the weight of the solid, say 

 a lump of marble, in the ordinary way. Determine 

 its apparent loss of weight when under water, as 

 described in Experiment 28. Since this loss is equal 

 to the weight of the displaced water, the volume of the 

 displaced water is easily found, and hence the volume 

 of the body which displaced it. 



The determination of the density, or of the specific 

 gravity, of such an irregular solid only requires one 

 further step to be made in the argument. Thus, to 

 find the density of marble, the weight of the marble 

 obtained in the above experiment has only to be divided 

 by the volume found as shown. 



