2:20 Mr. A. B. Northcotc on Parathionic Acid, 



Rations from alcohol, yielded long prismatic crystals, colourless 

 and transparent, but presenting a silky lustre when dried and 

 matted together : they were perfectly soluble in alcohol, and 

 contained no adherent sulphate of potassium, for they yielded no 

 precipitate with chloride of barium until after their ignition. 

 With this substance the experiments subsequently to be men- 

 tioned were made. 



It could scarcely be doubted that the body originated with 

 the alcoholic solution of potash ; yet in order to avoid the chance 

 of error having crept in by means of the complication with the 

 wax-alcohol, or the ethylic alcohol with which its sulphuric solu- 

 tion had been diluted before the neutralization, the remaining 

 portion of the original alcoholic solution of potash was neutralized 

 by simply adding it to some pure sulphuric acid diluted with 

 water to prevent any great rise of temperature. The filtrate 

 from the sulphate of potassium was then distilled ; alcohol with 

 a slight odour of aldehyde came over, and the residue, when crys- 

 tallized twice from alcohol, presented precisely the same features 

 as the salt formerly described. The substance therefore obvi- 

 ously came from the alcoholic solution of potash. This specimen 

 I have not analyzed ; for the quantities I had to deal with being 

 small, I was anxious to preserve' it for future experiments, or 

 until I could produce it from solution of potash in alcohol at 

 will, an endeavour in which 1 have not hitherto been successful. 

 The parathionate of potassium does not appear to have been pre- 

 pared by those who have worked upon these substances, but I 

 hope soon to be able strictly to compare it with the salt which I 

 have thus obtained. 



The observations which I have made upon the first-named 

 specimen of this salt are as follows. The substance undergoes 

 no change, nor does it attract moisture when exposed to the air. 

 It crystallizes well from alcohol, whether aqueous or absolute, in 

 long colourless prisms, which present the appearance of silky 

 needles when dried. These crystals withstand a temperature of 

 185° C. without decomposition or fusion; and inasmuch as a 

 portion heated above that temperature underwent no loss of 

 weight, it may be inferred that it contains no water of crystalli- 

 zation. It is very soluble in water; and by the spontaneous 

 evaporation of its aqueous solution the original substance sepa- 

 rates without increase of weight, and therefore in the anhydrous 

 form. Its aqueous solution produces no precipitate in solutions 

 of barium, lead, silver, cupric, mercurous, or mercuric salts. At 

 188° to 190° C. it fuses, and bubbles of gas form simultaneously 

 in the mass ; slight vinous and oily odours are perceptible, and 

 a few drops of liquid condense which are neutral to test-paper. 

 As the temperature rises, the substance undergoes a very slight 



