183 TEAR-BOOK OP FACTS. 



with great brilliancy on dissolving in hydrochloric acid some of the 

 crust deposited in boilers and kettles, and bringing a drop of the 

 solution into the flame of the apparatus. The shallow waters appear 

 to be rather richer in Li and Sr than the deep-weli waters ; the 

 presence of Li in the latter can, however, easily be demonstrated in 

 an ounce or even in half an ounce of the water. 



The following are the waters examined: — Thames water, taken at 

 low and high tide, Westminster Bridge ; also two samples as supplied 

 by the Chelsea and Lambeth Water Companies. Water supplied by 

 the New Ptiver Company ; and water from the under-mentioned 

 wells : — 



Duck Island Well, St. Jaraes'3 Park . ~) Above the London 



Pump II, Lincoln's Inn j clay. 



Burnett's Distillery, Yauxhall . . ") From the sand above 



Whitbread's Brewery, Chiswell-street . J the chalk. 



Guv's Hospital well . . . . )-, ,, 

 Trafalgar-square well .... j^ nillk - 



The above waters may be taken to represent the whole of the 

 London supply, since, besides the specimens from the Thames and 

 New River, others from the three principal water-bearing strata of 

 London are included. 



To guard against all possible sources of fallacy, the waters were 

 evaporated in platinum vessels, and all filtration avoided. It need 

 scarcely be mentioned that the alcohol, HO, SO :) , and HC1 used 

 were free from lithium and strontium. — Philosophical Magazine, 

 No. 134. 



NEW DYE-COLOUUS. 

 Aestkuse science has brought to light various substances, which 

 have lately proved valuable accessories to the resources of the 

 calico-printer. Thus (says Professor Grace Calvert, in a paper lately 

 read by him to the Poyal Institution) Dr. Prout, BOme thirty or forty 

 years ago, made the curious discovery, that uric acid possessed (ho 

 property of giving a beautiful red colour, when heated with nitric 

 acid and then brought into contact will' ammonia. The substance 

 thus obtained was further examined by Messrs. Liebig and Wohler, 

 in .' series, of researches which have been considered as amongst the 

 most important ever made in organic chemistry ; and this substance 

 thej called Mwemde, Jn the course of these investigations, they 

 also discovered a white crystalline substance called Alloxan. For 



twenty years both these substances were only to be found in the 

 laboratory; but in lSf<l l>r. BaM observed that alloxan, when in 



oontaol with the band, tinged it red. This led him to infer that 



alloxan might be employed to <lyu woollens red ; and farther experi- 

 ments convinced him that if woollen cloths were pn pared with per- 

 im. h ted through a tx>lution of alloxan and then submitted 

 to a gentle beat, a most beautiful and delicate pink colour resulted. 

 Subsequently murexide was employed and applied lucoesafully by 



M. DeponiUy, of l'aris, to dyeing wool and silk, and to printing 

 calicos, by the aid of oxido of lead and chloride of mercury as mor- 



