CHEMISTRY. 205 



brown flocculent precipitate of metallic arsenic appears. 

 Polytech. Jour. 



Detection of Gold. W. Skey, analyst to the .Geological Survey 

 of New Zealand, proposes to treat the roasted ore with a solution 

 of iodine (in alcohol) or of bromine (in water). To the resulting 

 solution, after concentration, may be applied the ordinary tests for 

 gold. If Swedish filtering-paper be dipped into such a solution 

 containing gold and subsequently incinerated, the ash will have a 

 purple color. The identification of gold by the combustion of the 

 salts with filtering-paper, it is suggested by Mr. Skey, seems to 

 promise a rapid method of estimating this metal by the aid of a 

 series of prepared test-papers representing gold in different 

 degrees of dilution. Chemical News. 



Reagent for Strychnia. When strychnia is well moistened with 

 concentrated sulphuric acid, there ensues, on addition of 

 proto-sesquioxide of cerium, a fine, blue coloration, turning to 

 cherry-red. As small a quantity as 0.000001 grain can thus be 

 detected. Other alkaloids treated in the same way give, bru- 

 cine, ayellow coloration ; morphine, brown ; narcotine, first brown, 

 then cherry-red ; quinine, pale yellow ; cinchonine remains color- 

 less. Sonnenschein. Ber. deutsch. diem. Ges., No. 12, 1870. 



Detection of Logwood Color in Wines. J. Lapeyr&re uses for 

 the detection of logwood in wines slips of fine filter-paper (Swedish 

 preferred) soaked, in an aqueous solution of neutral acetate of 

 copper ; one of these slips is dipped into the suspected wine and 

 then rapidly and carefully dried. The color of the paper after 

 drying should be gray or grayish-red ; if, however, logwood be 

 present, the color will be of a distinct sky-blue. 



Estimation of Grape Sugar. Karl Knapp. The author pro- 

 poses a method for the determination of grape sugar, based on 

 the fact that this substance reduces metallic mercury of a solution 

 of mercuric cyanide. As determined by experiment, 400 milli- 

 grams of mercuric cyanide are reduced by 100 milligrams of 

 grape sugar. The standard solution is prepared by dissolving 10 

 grains dry mercuric cyanide in water, adding 100 c. c. of a solution 

 of caustic soda of 1.145 sp. gr., and diluting to 1,000 c. c. Of 

 this solution, 40 c. c. (an amount corresponding to 100 milligrams 

 pure grape sugar) is heated to boiling in a porcelain dish, and the 

 solution of sugar under examination is then added until the 

 mercury is completely reduced, the end of the reaction being 

 marked by the failure of sulphuretted hydrogen to blacken a piece 

 of tine filter-paper moistened with a drop of the solution. This 

 test is superior to Fehling's, inasmuch as the standard solution is 

 easily prepared and keeps well ; less time is also required for the 

 determination, and foreign substances which hide the color of the 

 cuprous oxide do not interfere with the reduction of the mer- 

 cury. Annalen d. Chem. und Pharm. 



Phosphoric Acid from Iron Furnace Slag. When pig iron con- 

 taining phosphorus is converted into wrought iron, the phospho- 

 rus is eliminated, and is found in the furnace cinder, as phosphate 

 of iron. The amount of phosphorus varies, of course, with the 

 pig used, that from the Cleveland pig containing from 3 to 7 per 



