fl SIXTH REPORT — 1836. 



According to the statement of Zimmermann*, formerly Pro- 

 fessor of Chemistry at Giessen, all the above matters are to be 

 found in snow-water, but pyrrhine was first detected in a red 

 shower of rain which fell at that town in 1821. The Avater that 

 contained it was of a peach red colour, and flakes of a hyacinthine 

 tinge floated on its surface. This latter was the substance de- 

 signated by the above name. 



Some of these results have been since confirmed by Dr. Wit- 

 tingt, of Hoxter on the Weser, who declares, that he has ten times 

 examined the rain-water from his own neighbourhood, and that 

 whilst in seven trials he found it destitute of fixed principles, in 

 three he detected in it foreign matter, which in one case proved 

 to be muriate of potash, and in the other two free muriatic acid. 

 He also found the air collected from elevated spots on the Hartz 

 mountains to contain the same organic principle which Zimmer- 

 mann had designated as pyrrhine, thus confirming the probabi- 

 lity of its existence in rain-water. 



He remarked, that the atmosphere of a place contained in 

 general the same foreign ingredients which the first fall of rain 

 brings to the ground, such, for example, as traces of muriates, 

 "if free muriatic and carbonic acids, and of carburetted hydrogen 

 gas. Rain which fell during a north-west wind connnonly con- 

 tained much carbonic, together with traces of phosphoric, acid. 

 The latter was discovered on several occasions in rain which 

 had fallen during particular states of the weather; and Dr. 

 Witting goes on to state, that certain plants exhale it, so that 

 when they are confined under glass, traces of this acid may be 

 detected on the internal surface of the latter. 



In four out of twelve trials snow was found to exhibit signs 

 of muriatic acid, and of an organic colouring matter. Hal! and 

 sleet collected in the spring of 1824 contained a large quantity 

 of this latter substance, but none either of the acids nor the salts 

 above mentioned. Dew showed vestiges of nitric and muriatic 

 acids, but in hoar-frost no signs of any extraneous matter were 

 discoverable. 



Upon the whole then it may be observed, that of the above 

 circumstances, the one relating to the existence of organic mat- 

 ter in atmospheric water is best substantiated ; and this has more 

 lately been ascribed by the distinguished Ehrenberg to the ova 

 of a ipartlcular class of Infusoria (the Polygastrica), which, being 

 raised by currents and by evaporation, fill the atmosphere, and 

 thus produce the pyrrhine observed by chemists X- The presence 

 of salts and of acids, in the atmosphere, and consequently in 

 water derived from it, is also supported by sufficient evidence. 



* Kastner's Arcliiv., vol. ii. t Kastner's Arcliiv, vol. v. 



\ Ehrenberg in Jameson's Journal for 1831, "on Blood-red Water." 



I 



