Ohervatiom on the Figure of the Planet Saturn. 14/ 



100 grains of the stone to be examined in very fine pow- 

 der, must be fused for about half an hour, at a strong red 

 heat, in a crucible of platina or silver, with 200 grains of 

 boracic acid. 



An ounce and half of nitric acid, diluted with seven or 

 eight times its quantity of water, must be digested upon the 

 fused mass till the whole is decomposed. 



The fluid must be evaporated till its quantity is reduced 

 to an ounce and half or two ounces. 



If the stone contain silex, this earth will be separated 

 in the process of solution and evaporation ; and it must 

 be collected upon a filter, and washed with distilled water 

 till the boracic acid and all the saline matter is separated 

 from it. 



The fluid, mixed with the water that has passed through 

 the filter, must be evaporated, till it is reduced to a con- 

 venient quantity, such as that of half a pint ; when it must 

 be saturated with carbonate of ammonia, and boiled with 

 an excess of this salt, till all the materials that it contains, 

 capable of being precipitated, have fallen to the bottom of 

 the vessel. 



Tlie solution must then be separated by the filter, and the 

 earths and metallic oxides retained. 



li must be mixed with nitric acid till it tastes strongly 

 sour, and evaporated till the boracic acid appears free. 



The fluid must be passed through the filter, and subjected 

 to evaporation till it becomes dry ; when, by exposure to a 

 heat equal to 450" Fahrenheit, the nitrate of ammonia will 

 be decomposed, and the nitrate of potash or soda will re- 

 main in tlie vessel. 



It will be unnecessary for me to describe minutely the 

 method of obtaining the remaining earihs and metallic oxides 

 free from each other, as I have used the connnon processes. 

 1 have separated the alumine by solution of potash, the lime 

 by sulphuric acid, the oxide of irou by succinate of am- 

 monia, the manganese by hydrosulphuret of potash, and 

 the magnesia by pure soda. 



XXXIV. Olservatiovs on the singular Figtireofthe Planet 

 Saturn. By William Herschbll, LL. D. F. R. S.* 



JL here is not perhaps another object in the heavens that 

 presents us with su.ch a variety of extraordinary phaenomena 



* {loro Um Traryiattioni oflht Rtyai Society for ISOJ. 



