140 



AMMONIA. 



Upon this variation in density of solutions of ammonia in proportion to their 

 strength, Mr. J. J. Griffin has constructed a useful instrument called an Ammonia-meter. 

 It is founded upon the follo\ving facts : That mixtures of liquid ammonia with -water 

 possess a specific gravity which is the mean of the specific gravities of their com-* 

 ponents ; that in all solutions of ammonia, a quantity of anhydrous ammonia, weigh- 

 ing 212J grains, which he calls a test-atom, displaces 300 grains of water, and reduces 

 the specific gravity of the solution to the extent of -00125 ; and, finally, that the 

 strongest solution of ammonia which it is possible to prepare at the temperature of 

 62 F. contains in an imperial gallon of solution 100 test-atoms of ammonia. 



We extract the following paragraph from Mr. Griffin's paper in the Transactions 

 of the Chemical Society, explanatory of the accompanying Table : 



' The first column shows the specific gravity of the solutions ; the second column the 

 weight of an imperial gallon in pounds and ounces ; the third column the per-centage 

 of ammonia by weight ; the fourth column the degree of the solution, as indicated by 

 the instrument, corresponding with the number of test-atoms of ammonia present in a 

 gallon of the liquor ; the fifth column shows the number of grains of ammonia con- 

 tained in a gallon ; and the sixth column the atomic volume of the solution, or that 

 measure of it which contains one test-atom of ammonia. For instance, one gallon of 

 liquid ammonia, specific gravity 880, weighs 8 Ibs. or 128 oz. avoirdupois ; its per- 

 centage of ammonia, by weight, is 33-117 ; it contains 96 test-atoms of ammonia in one 

 gallon, and 20400-0 grains of ammonia in one gallon ; and, lastly, 104-16 soptems 

 containing one test-atom of ammonia. Although no hydrometer, however accurately 

 constructed, is at all equal to the Centigrade mode of chemical testing, yet the Ammo- 

 nia-meter, and the Table accompanying it, will be found very useful to the manu- 

 facturer, enabling him not only to determine the actual strength of any given liquor, 

 but the precise amount of dilution necessary to convert it into a liquor of any other 

 desired strength, whilst the direct quotation of the number of grains of real ammonia 

 contained in a gallon of solution of any specific gravity will enable him to judge at a 

 glance of the money- value of any given sample of ammonia.' 



Table of Liquid Ammonia (Griffin). 



One Test-Atom of Anhydrous Ammonia =NH* weighs 212-5 grains. 

 Specific Gravity of Water =1-00000. One Gallon of Water weighs 10 Ibs., and con- 

 tains 10,000 Septems. Temperature 62 F. 



