LAKD AND LARD ADULTERATIONS. 433 



Therefore a bob which displaces 5 g of water at 35 has a volume 

 5.029cc. Tliis volume of water at 4 would weigh, therefore, 5.029 g. 

 The above specific gravity referred to water at 4 would be 4.5725-i- 

 5.029 =.9092. 

 In tabular form the above data are as follows : 



Grams. 



Weight of 5.029ccoilat 35.... 4.5725 



Weight of 5.029cc water at 35 5.0000 



Weight of 5.029cc of water at 4 5.0290 



Relative weight of oil at 35 to water at 35 equals 9145 



Relative weight of oil at 35 to water at 4 equals 9092 



The change in volume of a fat or oil for each, degree of temperature 

 is approximately .OOOTcc for each cubic centimeter of the oil. The 

 weight of a given volume of an oil having been determined at any 

 temperature, its weight at the required temperature can be approxi- 

 mately calculated. 



Thus, in the above case 



Grams. 



5.029ccof oil at 35 weighs 4.5725 



Then 5.029cc of oil at 4 weighs 4.6707 



Then relative weight of oil at 4 to water at 4 equals 9307 



Then relative weight of oil at 4 to water at 35 equals 9342 



ESTIMATION OF THE SPECIFIC GRAVITY OF FATS, STEARINES, ETC., 

 IN A SOLID CONDITION.* 



(a) Estimation of specific gravity at zero. A platinum crucible con- 

 taining about 20cc is furnished with a fine platinum bail, which is fast- 

 ened through two small holes drilled into the crucible at opposite points 

 near the upper edge. To the handle of the crucible at the central point 

 is fastened a fine platinum wire, furnished with a loop above, by means 

 of which it is suspended from the hook of the balance. The crucible is 

 weighed empty and then in water at zero. This is accomplished in the 

 following way: 



The pan of the balance is proteced by a wooden bench in the ordinary 

 way in taking specific gravities, and on this bench is placed a large 

 beaker glass containing a smaller one. The space between the two 

 beakers is filled with finely-powdered ice and the small beaker is nearly 

 filled with distilled ice-water. The platinum crucible is suspended at 

 such a height as to allow it to be wholly immersed in the water, includ- 

 ing the bail and a small portion of the suspending platinum wire. The. 

 weight of the crucible having been determined in the water, it is taken 

 out, carefully dried, and about 15 grams of the filtered and melted fat 

 placed in it. The fat is allowed to solidify slowly at ordinary tempera- 

 tures. The crucible with fat is then weighed in the air and placed in 



* Wollny, Milch Zeitung, 1888, No. 25 et seq. 

 17319-pt. 4 3 



