CHEMISTRY. 



decomposing all classes of minerals little less 

 than that possessed by hydrochloric acid, and 

 that this very difference in degree gives the 

 organic acid an advantage over the mineral 

 acid in the determination of species. Besides 

 treating the minerals with a saturated solution 

 of citric acid, he examined the action of the 

 same solution, to which solid sodium nitrate is 

 added. This mixture proves to be a very pow- 

 erful solvent, dissolving bismuth, antimony, 

 arsenic, copper, lead, tin, mercury, and silver, 

 and nearly all the natural sulphides. The ad- 

 dition of solid potassium iodide to the solution 

 of citric acid also greatly increases its decom- 

 posing power. Applying these reagents to 

 minerals, Dr. Bolton obtained the following 

 results: 1. Complete solution of carbonates, 

 with liberation of carbonic-acid gas. 2. More 

 or less complete decomposition of oxides, phos- 

 phates, etc. 3. More or less complete decom- 

 position of sulphides, with liberation of sul- 

 phuretted hydrogen. 4. Decomposition of sul- 

 phides, with oxidation of the sulphur. 5. De- 

 composition of silicates, with separation of 

 slimy or gelatinous silica. 6. Decomposition 

 of certain species, with formation of character- 

 istic precipitates. 7. Wholly negative action. 

 The portability of the reagents in a dry state 

 makes this method conveniently applicable in 

 field-work. The relation of the reactions de- 

 scribed to the geological work of the organic 

 acids of the soil is a point of much importance, 

 and merits further researches. 



Purification of Water. A new method of 

 purifying and filtering water has been used for 

 more than three months at the Royal Aquarium, 

 London, with complete and satisfactory success, 

 in furnishing a constant supply of perfectly 

 clear water. The water, as it is furnished by 

 the water companies, is first exposed in the 

 softening cistern to a jet of lime-water which 

 coagulates the clay that is held in suspension 

 and causes the impurities to be deposited, and is 

 afterward passed into a filter so constructed as 

 to expose a very large filtering surface, and so 

 arranged that it can be cleaned by mechanism 

 in a few minutes every day, and oftener, if 

 necessary. The apparatus is capable of deliv- 

 ering from eighty to one hundred gallons of 

 pure water per square foot of surface per hour, 

 while the ordinary rate of filtration through 

 sand-beds is said to range from two to six gal- 

 lons per square foot per hour only. The use 

 of the system has been attended with a great 

 improvement in the condition of the fishes in 

 the tanks to which it has been applied, and a 

 decrease in the rate of mortality among them. 

 It has been adopted in several private estab- 

 lishments, and its application to the public 

 water-supply has been suggested. 



A plan possessing similar features, but adapt- 

 ed to a more extended scale of operation, is in 

 use for purifying the waste-waters of the great 

 paper-mills at Essonne, France, and has been 

 suggested as likely to furnish the most feasible 

 means, when still further enlarged, for solving 



the difficult questions connected with the puri- 

 fication and disposition of the sewage-waters 

 of Paris. 



Bromide of Ethyl a an Ancesthetic. Bro- 

 mide of ethyl has been recommended as an an- 

 aesthetic, preferable in many respects to ether 

 and chloroform. Dr. R. J. Levis, of the Penn- 

 sylvania and Jefferson College Hospitals, Phil- 

 adelphia, reports of it that, so far as he has 

 observed, after several months of experience in 

 using it, it does not influence the circulation, 

 except sometimes to produce a slight increase 

 in the rapidity of the heart's action and in ar- 

 terial pressure. Respiration is but little affect- 

 ed by it, beyond its producing the ordinary 

 characteristics of all anesthetic sleep. Nausea 

 and vomiting occur less frequently with it than 

 with ether or chloroform. It vaporizes read- 

 ily, and seems to be entirely eliminated through 

 the lungs. Its vapor produces no irritation in 

 the respiratory passages. General excitement 

 and the tendency to struggle occur far less fre- 

 quently when it is used than in the early stages 

 of the anesthesia of ether, and, apparently, 

 even than in that of chloroform. Complete 

 anaesthesia is accomplished, it is estimated, in 

 about one third less time than is the case with 

 chloroform, and recovery from the effect is 

 even comparatively more rapid, the time re- 

 quired for recovery generally not exceeding 

 two minutes after the inhalation has ceased. 

 The recovery is so complete that the patient is 

 often able to stand and to walk immediately 

 after awakening. Insensibility is usually pro- 

 duced in from two to three minutes. The 

 completion of the effect is clearly shown by 

 the dilatation of the pupils, which resume their 

 normal condition when the sentient state re- 

 turns* The vapor of this substance is not in- 

 flammable, so that it is free from the danger 

 which attends the use of ether in the presence 

 of artificial lights. The ordinary essentials of 

 the proper and safe production of anesthesia 

 must not, however, be dispensed with in the 

 use of the new agent, for its safety is only com- 

 parative, and is not yet proved to be absolute. 



Improved Test for Sugar. Mr. William L. 

 Dudley, of the Miami Medical College, Ohio, 

 observing that Bottger's test for sugar, with 

 snbnitrate of bismuth and sodium carbonate or 

 sodium hydrate, is liable to error on account 

 of the subnitrate being liable to contain silver, 

 and occasionally other impurities, proposes the 

 following modification of it : Dissolve subni- 

 trate of bismuth in the least possible quantity 

 of chemically pure nitric acid, and add to it an 

 equal amount of acetic acid of ordinary strength. 

 To the solution to be tested, add sufficient so- 

 dium hydrate to render it strongly alkaline ; 

 then add a drop or two of the bismuth solu- 

 tion ; heat to boiling, and continue the boiling 

 for a short time (twenty to thirty seconds). 

 If sugar is present, the white, flocculent pre- 

 cipitate, which formed on the addition of the 

 bismuth solution to the alkaline liquid, will be- 

 come gray or black. The depth of color of the 



