Chemistry. 409 



filter, and can then be purified by proper treatment, when it will have all 

 the chemical properties mentioned in my former article of what I pre- 

 sumed to be rosalic acid obtained from the treatment of phenylic acid. 



Tacony Chein. Laboratory, (Bridesburg,) Philadelphia, Aug. 7, 1862. 



10. Thallium. — Crookes has sent us an early copy of his ''Preliminary 

 researches on Thallium'" from the Proceedings of the Royal Society. 

 Crookes' discovery of this new metallic element was published March, 

 1861, and therefore completely antedates the paper of Lamy, an abstract 

 of which is given on page 275-6 of this volume. The name Thallium, 

 is derived from the Greek OaUog, or Latin thallus, a budding twig, — a 

 word which is frequently employed to express the beautiful green tint of 

 young vegetation, chosen on account of the green line which it commu- 

 nicates to the spectrum, recalling with peculiar vividness the fresh color 

 of early spring. 



It appears from Crookes' researches that thallium is by no means a 

 very rare substance ; he has found it in many mineral ores from various 

 localities. It was present in more than one eighth of the specimens in a 

 large collection of cupiferous pyrites from ditferent parts of the world — he 

 has rarely found it however in pyrites in which copper was absent. In 

 most cases it is only necessary to powder a small fragment of the mineral 

 and iguite a little of it in the flame on a moistened platinum wire, when 

 the green line is distinctly seen in the spectroscope. The author thinks 

 that in some of the large English copper, sulphur and sulphuric acid 

 works, thallium is now thrown away by the hundred weight : a slight 

 modification of the present arrangements of the furnaces and condensing 



the whole of this to be saved. Owing to the frequent occurrence of thal- 



be present in commercial copper and may give rise to some of the well 

 known but unexplained difterences of quality. 



The author finds the following the most advantageous method for ex- 

 tracting the new element from sulphur or pyrites: 



it as completely as possible in 

 n of nitric acid until all solvent 

 _ er. Evaporate down to drive off 



■ess of'nitricaddT add" a little sulphuric acid if necessary, and take 

 at the solution does not get dry, or even pasty. Then dilute with water, 

 It gently, to be certain of getting ail the soluble portion dissolved, 

 if lead be present, the greater portion will be left behind m this opera- 

 the form of insoluble sulphate. Dilute the filtrate considerably, and 

 lolution of carbonate of soda^until^ tlie reacdon "^^j^'^^jy^jj^^l'^"^' 



aeing passed through the liquid precipi^ti 



LTnlThTy'S^^^pan^lJie^^^^ ?° '^^^^J ^ 



Ivedoutby warm dilute sulphuric acid, which has scarcely any s 



the sulphid of mercury by bemg Doiiea m inou.« 

 which the sulphid of mercury IS insoluble. Ihese 



