4-20 Intelligence and Miscellaneous Articles. 



It appears to result from the observations of MM. Einbrodt and 

 Unger, that the substance lately found in guano by the latter is not 

 identical with xanthic oxide ; according to them xanthic oxide is 

 OH. 4 N 4 2 ; and guanine, which was mistaken for the same substance, 

 is C 5 H 5 N*0. 



M. Unger also observes that guanine yields, by nitric acid, an acid 

 which crystallizes in small regular prisms, which are but slightlv 

 soluble in water, and possess the composition of uric acid, plus oxygen 

 and the elements of water. M. Unger confines himself to indicating 

 C 10 H 10 N 8 O 9 , which probably relates to the anhydrous and hypo- 

 thetical acid ; to this must be added H~ O in order to designate the 

 real and free acid, that is C 10 H 12 N s O 10 , or rather O H 6 N* O 5 in 

 M. Gerhardt's notation. — Journ. de Pharm. et de Ch,, Septembre 

 1846fj[ B .j X {j \ -IQ3&W mil dJivr gnL 



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TINCTURE OF LOGWOOD AS A TEST FOR BICARBONATE OF LIME. 



M.Dupasquier states that he employs spirituous tincture of logwood 

 to discover bicarbonate of lime in spring water ; according to this 

 chemist the tincture should be prepared, either cold or with heat, 

 with logwood recently cut and divided. The tincture has a brownish 

 colour, and three or four drops being added, instantly communicates 

 a fine violet colour to water which contains the least trace of bicar- 

 bonate of lime. In a water which contains "any other salt of lime, 

 it occasions only a pale yellowish colour. 



Selenitic waters, containing bicarbonate of lime, give the former 

 appearance when cold, whereas after being boiled so as to decompose 

 the last bicarbonate, the second reaction ensues from the sulphate 

 of lime. f 0fl 9J j| Tjr oisdi ^jlTsmai buollnO .M 



According to M. Dupasquier, the bicarbonate of lime, which is 

 held in solution either in spring or river water, acts upon the colour- 

 ing principle of the logwood in the same manner as the alkalies or 

 the soluble neutral alkaline carbonates. — Journ. de Chim. Mid., 

 Septembre 1846. , Q b byraici 9J«Jiqh>an 



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ON THE TREATMENT OF OSMIURET OF IRIDIUM. 



Instead of acting upon the osmiuret of iridium by calcination with 

 common salt in a current of chlorine, M. Fritzsche prefers fusing 

 this mineral with a mixture of chlorate and caustic potash. 



For this purpose he fuses over a lamp, in a capacious porcelain 

 crucible, equal parts of the chlorate of potash and caustic potash, 

 and introduces the osmiuret of iridium. If the heat be continued, 

 the oxygen which is set free attacks the mineral, which is soon ob- 

 servable by the yeilowish-brown colour of the mass; this swells 

 considerably and becomes gradually thicker ; as soon as the action 

 is over the product is black and sinks. During this operation no 

 vapour of osmium is disengaged ; but some is produced if the heating 

 of the mass is continued ; this is, however, useless as soon as the 

 action is complete and the mass has become soluble in water. Sixty 



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