CHEMISTRY. 



lead, which is then separated by filtration and 

 treated for the production of iodine or iodides. 

 After filtration the liquid is boiled, nitrate of 

 soda is added to convert the chloride of potas- 

 sium present into nitrate of potash. The latter 

 is separated by crystallization. There remains 

 a solution of common salt containing traces of 

 ammonia from the previous soda operation, 

 and a trace of chloride of potassium. This so- 

 lution is again treated by the ordinary ammonia- 

 soda process for the production of bicarbonate 

 of soda and white alkali. 



Solubility of Tin, Antimony, and Arsenic, 

 in Nitric Acid. Mr. George Hay, in a com- 

 munication to the Academy of Natural Sciences 

 of Philadelphia, states the results of experi- 

 ments made by him, which prove that not only 

 is tin converted into a soluble salt by concen- 

 trated nitric acid, but that protonitrate of tin 

 is formed. He also details similar experiments 

 with arsenic and antimony. The circumstances 

 under which the salt of tin was found were as 

 follows : A dry test-tube holding a little con- 

 centrated nitric acid was floated in a vessel of 

 water at a temperature of 36 Fahr. A frag- 

 ment of pure tin dropped into the acid became 

 coated with a white substance, and after fifteen 

 minutes was entirely transformed into this 

 white substance. Other fragments added at 

 intervals were in like manner transformed. The 

 contents soon presented a gelatinous appear- 

 ance, but, upon the addition of about two 

 volumes of water, the whole became a clear 

 and colorless fluid, thus holding the tin in so- 

 lution and proving that the white substance 

 was not hydrate of metastannic acid. The so- 

 lution was tested as follows : 1. A portion was 

 boiled, and the whole of the dissolved metal 

 was precipitated as hydrate of metastannic 

 acid. 2. After neutralizing a portion of the 

 free acid remaining in the tube, hydrosulphuric 

 acid caused the precipitation of protosulphide 

 of tin mixed with sulphur. 3. To a portion of 

 the original solution was added a solution of 

 the chloride of mercury, and in the course of 

 a few hours a white precipitate, subchloride 

 of mercury, was formed. 4. Chloride of gold 

 gave no precipitate. 5. Potash solution gave a 

 white precipitate, soluble in excess of potash. 

 6. To a mixture of ferricyanide of potassium 

 and sesquichloride of iron was added a por- 

 tion of the original solution, the result being, 

 after a few hours, Prussian blue. These tests 

 were retarded by the presence of a large excess 

 of nitric acid, and the production of purple of 

 Cassius was entirely prevented by the same 

 cause. To obviate this difficulty a fresh solu- 

 tion was prepared by adding the metal to the 

 acid until the contents of the tube had become 

 thick and pasty, and there appeared to be no 

 farther action going on. Water was now 

 added, but in this instance some of the white 

 substance remained undissolved. The solution 

 was filtered and the clear filtrate tested as be- 

 fore, with more satisfactory results. 



The next experiment was with antimony. 



Into a dry test-tube about two cubic centi- 

 metres of concentrated nitric acid was poured, 

 and then about twenty grains of powdered 

 antimony added. This was floated in water at 

 36 Fahr., and allowed to remain for twelve 

 hours, being shaken occasionally. Gradually 

 the fluid became green, and at the end of 

 twelve hours the solution was strongly green. 



On decanting this and diluting with water, an abun- 

 dant white precipitate was produced, showing that 

 a liirge proportion of the antimony had been dis- 

 solved in the nitric acid. In order to ascertain in 

 what state of combination the antimony was held, the 

 following experiments were made: Tartaric acid 

 was added to the fluid containing the precipitate, 

 and it at once dissolved to a colorless fluid. The 

 fluid was now filtered in order to remove any parti- 

 cles of undissolved metal which might have been 

 decanted. 1. After neutralizing a portion of the 

 free acid in a portion of the filtrate, a strong solution 

 of hydrosulphuric acid was added the result was a 

 bulky, orange-red, unmistakable precipitate of ter- 

 sulphide of antimony, readily soluole in potash, and 

 reprecipitated from its alkaline solution by dilute 

 hydrochloric acid. 2. To another portion of the fil- 

 trate, potash was added, and a white precipitate of 

 teroxide of antimony was obtained soluble in excess. 

 3. To the alkaline solution last obtained, nitrate of 

 silver was added, and there was obtained a jet-black 

 precipitate of suboxide of silver insoluble in excess 

 of ammonia this being distinctive of Peroxide of 

 antimony. 4. Another portion of original filtrate was 

 neutralized by ammonia to remove free nitric acid, 

 and then acidulated with hydrochloric acid. A drop 

 or two of the solution thus obtained was put upon 

 a clean surface of platinum, and a fragment of zinc 

 introduced the result was a dark-brown or black 

 stain of metallic antimony not removable by cold 

 hydrochloric acid, but removable by hot nitric acid. 

 These four tests snow that the original solution con- 

 tained teroxide of antimony z and, as the solution 

 was obtained by means of nitric acid, the probability 

 is that it was a ternitrate of antimony, for a large 

 quantity of the metal was dissolved. The HS pre- 

 cipitate was so bulky as at first almost to fill the 

 test-tube. Boiling the original green solution gave 

 an abundant white precipitate of antimonic acid ac- 

 companied by copious evolution of orange-red fumes. 

 Boiled till the red fumes had disappeared diluted 

 and filtered the filtrate did not pass through clear, 

 but on passing twice more through the same filter 

 was obtained a perfectly clear filtrate. This filtrate 

 gave every one of the four tests above mentioned 

 with the utmost readiness. In this case no other 

 acid but the nitric had been used. Arsenic treated 

 in the same manner yielded a green solution which 

 answered all of the tests for arsenic acid, giving, 

 under the proper treatment, tersulphide and penta- 

 sulphide of arsenic, arsenate of silver, etc. 



A New Oxide of Sulphur. The cause of the 

 intense blue color produced by the action of 

 sulphur on sulphuric oxide, or on disulphuric 

 acid, is shown by R. Weber to be due to a new 

 sulphur-oxide, first isolated by himself. To 

 obtain it, a portion of sulphuric oxide is pre- 

 pared, containing sulphuric acid, and into this 

 is thrown, in small portions at a time, care- 

 fully-dried flour of sulphur. The sulphur is 

 instantly converted into dark-blue liquid drops, 

 which sink to the bottom and solidify. The 

 temperature must be kept at 15 C., as below 

 this point the whole liquid solidifies, and above 

 it the blue substance decomposes. After the 

 operation the excess of liquid is poured off, 



