82 ESSAY V. 



mixed with the melted green mass, an effervescence ensues 

 (Sec. xxxvi. (&)), and the mass assumes a light grey colour ; 

 it likewise yields a white solution with water ; what remains 

 on the filter is phlogisticated manganese, (i) If finely 

 powdered arsenic be added to such an alkaline solution of 

 manganese during its state of fusion, the green colour also 

 disappears, and a white one is produced. If the mass be 

 dissolved in water, phlogisticated manganese is precipitated. 

 This is certainly a very remarkable phenomenon. I here 

 see that phlogiston actually enters into the composition of 

 arsenic. The same thing likewise follows from Sec. XXIL, in 

 which I mentioned that arsenic is capable of rendering the 

 solution of manganese in acids limpid. I here also recollected 

 the volatile nitrous acid that is produced by means of arsenic. 

 I thought, if the arsenic could be deprived of its phlogiston, 

 quite different properties would appear. The experiments 

 which I made according to this conjecture were crowned 

 with success, and I found out two ways of resolving arsenic 

 into its constituent parts, which are a peculiar acid, and the 

 universal inflammable principle. 



SECTION XXXIX. EFFECTS OF SAL AMMONIAC. 



(a) Half an ounce of phlogisticated manganese, mixed 

 with an equal quantity of powdered sal ammoniac, was 

 distilled in a glass retort. I obtained in the receiver dry 

 volatile alkali, and towards the end sal ammoniac in the 

 neck of the retort. (6) Half an ounce of pure phlogisticated 

 manganese (Sec. xxiv. (&), (c)), mixed with 2 drms. of pounded 

 sal ammoniac, were exposed to distillation, and I obtained 

 caustic liquid volatile alkali. Both the residuums in the 

 retort were fused ; they were soluble in water, (c) 1 oz. 

 of well-triturated manganese was distilled with half an ounce 



