168 Intelligence and Miscellaneous Articles. 



complete darkness ; that nevertheless in certain cases the proportion 

 is virtually the same under the two conditions. 



4. When normal air is replaced by pure oxygen, the differences 

 observed become much more marked. 



5. That the flower whose development is commencing, disengages 

 a little more carbonic acid than that which has attained its complete 

 development, which may be explained by a more powerful vital action. 



6. Every flower left in an inert gas disengages small quantities of 

 carbonic acid. 



7. We see, in conclusion, that, of the various elements constituting 

 the flower, the pistil and the stamina, in which the greatest vitality 

 resides, are those which consume the greatest quantity of oxygen, and 

 produce the largest proportion of carbonic acid. — Comptes Rendu s, 

 June 27, 1864. 



ON THE SPECTRAL RAY OF THALLIUM. BY M. J. NICKLES. 



I have found that there are compounds of thallium which do not 

 possess the property of colouring the flame green, and of developing 

 the characteristic spectral ray ; these are compounds with sodium, 

 and especially with chloride of sodium. By its flame and its yellow 

 rays this chloride completely hides the green ray. 



Although chloride of thallium is insoluble in cold water, it is not 

 so in water saturated with chloride of sodium. Thus, on pouring a 

 solution of the latter into acetate of thallium, a precipitate of chloride 

 of thallium is indeed formed, but the mother-liquors retain a consi- 

 derable quantity of the latter without colouring the flame green. If, 

 then, among the rays of the solar spectrum that characteristic of 

 thallium has not been found, nothing proves that this metal does 

 not exist in the sun ; for if it has not been found, sodium has, the 

 paralyzing action of which, when present in a certain proportion, I 

 announce in this Note. 



This incompatibility between the ray of sodium and that of thal- 

 lium ought to be taken into account in toxicological or medico-legal 

 researches directed upon thallium ; for when it is present in animal 

 tissues or liquids, it may be accompanied by sodium-compounds in suf- 

 ficient quantity to annul its action on the flame, and thus lead to 

 the supposition that this poisonous metal is absent. 



Thus, also, if thallium is to be sought in mineral waters or mother- 

 liquors, and generally in saline waters containing excess of chloride 

 of sodium, it must first be disengaged from the sodium compounds, 

 either by displacing it by means of pure zinc, or by means of the 

 battery, or by precipitation by hydrosulphate of ammonia or iodide 

 of potassium. 



In regard to the latter, I have assured myself that liquids containing 

 chloride or bromide of thallium in solution are precipitated by iodide 

 of potassium, which gives rise to an iodide of thallium of a beautiful 

 yellow colour, insoluble in the precipitating iodide but fairly so in 

 distilled water. — Comptes Rendus, Jan. 11, 1864. 





