156 Royal Society : — 



rical observations, and has ennobled our previous knowledge by 

 showing its relationship to some of the most sublime of natural 

 phenomena. 



Postscript, July 24. — As far back as the year 1822 Sir John 

 Herschel described the spectra of various coloured flames in the 

 Transactions of the Royal Society of Edinburgh. In his "Treatise 

 on Light" in the Encycl. Metropol., published in 1827, he describes the 

 spectra derived from the introduction of various salts into flames, 

 and finds exactly as Bunsen and Kirchhoff have recently found, the 

 muriates most suitable for such experiments, on account of their 

 volatility. He also adds the distinct statement, that " the colours 

 thus communicated by different bases to flame afford in many cases 

 a ready and neat way of detecting extremely minute quantities of them." 



ROYAL SOCIETY. 



[Continued from p. 77 -^ 



November 22, 1860. — Major-General Sabine, R.A., Treasurer and 

 Vice-President, in the Chair. 



The following communications were read : — 



" Contributions towards the History of the Monamines." — No. III. 

 Compound Ammonias by Inverse Substitution. By A. \V. Hofmann, 

 LL.D., F.R.S. &c. Received July 24, 1860. 



Many years ago I showed that the bromide or iodide of a quartary 

 ammonium splits under the influence of heat into the bromide or 

 iodide of an alcohol-radical on the one hand, and a tertiary monamine 

 on the other. 



Having lately returned to the study of this class of substances, I 

 was led to examine the deportment, under the influence of heat, of 

 the tertiary, secondary, and, lastly, of the primary monammonium- 

 salts. 



Experiment has shown that these substances undergo an ana- 

 logous decomposition. The chloride of a tertiary monammonium 

 when submitted to distillation yields, together with the chloride of an 

 alcohol-radical, a secondary monamine ; the chloride of a secondary 

 monammonium, together with an alcohol-chloride, a primary mona- 

 mine ; lastly, the chloride of a primary monammonium, the chloride 

 of an alcohol-radical and ammonia. 



Exactly, then, as my former experiments show that we may rise in 

 the scale by replacing the four equivalents of hydrogen in ammonium 

 one by one by radicals, so it is obvious from these new experiments 

 that we may also step by step descend, by substituting again hy- 

 drogen for the radicals in succession. 



To take as an illustration the monammouium-salts of the ethyle- 

 series which as yet I have chiefly examined : 



