Royal Society. 517 



action of light, while an alkaline sulphuret is essential to the 

 production of the other. The pink colour of the solution to 

 which sulphuret of potassium has been added, becomes soon 

 purple, and afterwards deposits a blue substance, which long 

 kept in the solution becomes white. This blue precipitate 

 cannot be prussian blue, for it is produced in an alkaline solu- 

 tion, and is instantly decolorized by acids. It is possible that 

 the above pink solution owes its colour to the same substance 

 as is present in Gregory's solution of sulphuret of azote in 

 caustic potash. 



I have brought forward these different instances of colora- 

 tion occurring in cyanogen compounds, because they seem 

 to point out the existence of a yet unexamined class of 

 prussiates. 



On the Acid Cyanurate of Potash. 



Mineral acids, as well as acetic acid, were found to have the 

 power of converting the neutral cyanate of potash into the 

 acid cyanurate. The essential circumstance in this process 

 is that the solution of the cyanate of potash be concentrated. 

 The process above described for making cyanate of potash by 

 calcining in the air the yellow prussiate of potash, affords a 

 ready means of making this salt easily, and in quantity. The 

 roasted prussiate is digested with cold water, filtered, and 

 muriatic acid, added to the precipitated salt, is dissolved in hot 

 water, and crystallized by cooling. 



The foregoing experiments were partly confirmed and partly 

 originally performed in the laboratory at Giessen, in 1838. 



This paper is the only scientific memorial of its amiable 

 author, who died about two years ago, at an early age, but 

 mature enough to have endeared him to many men of science, 

 and to have indicated promise of scientific eminence. He 

 will be most remembered by his friends for a marked recti- 

 tude of mind, combined with an uncommon ardour; evincing 

 itself in the warmth of kindly feelings and in the enthusiasm 

 of scientific pursuits. — T. C. 



LXXVIII. Proceedings of Learned Societies. 



ROYAL SOCIETY. 

 [Continued from p. 489.] 

 June 17, 1841. " f\N the Corpuscles of the Blood." Part III. By 

 (Continued.) " Martin Barry, M.D., F.R.SS. L. and E.* 



After remarking that no clear conception has hitherto existed of the 

 mode in which the floating corpuscles of the blood conduce to nou- 



[* Abstracts of Parts I. and II. of this memoir will be found in Phil. 

 Mag., S. 3. vol. xvii, p. 300, and vol. xviii. p. 310. — Edit.] 



