Chemistry and Physics. 157 



method, by the action of the copper-zinc couple on methyl iodide, 

 and was passed through three copper tubes 12 inches long, 1-5 

 inches in diameter, placed horizontally, fitted with corks and 

 connecting glass tubes and filled with copper-zinc and as much 

 alcohol as they would contain in this position, to remove the 

 vapor of the iodide; and then through a glass tube containing 

 beads moistened with sulphuric acid to absorb the alcohol vapor. 

 The methane was collected in a small gas-holder 5 liters in capac- 

 ity graduated to 5 c. c. and passed thence to the photometer, 

 which was furnished with a Methoen standard giving a light of 

 two candles when supplied with eighteen candle gas. The 

 methane was burned in a London argand with a six-inch chim- 

 ney, provided at top with a metal cap capable of vertical adjust- 

 ment by a screw. This cap is to limit the air supply and is 

 necessary at low rates of consumption. Two specimens of marsh 

 gas were tested. In the first 2*78 cubic feet (corrected) were con- 

 sumed per hour and gave a light of 2*9 candles ; or 5*2 candles 

 per cubic foot per hour. In the second 4*56 cubic feet were con- 

 sumed per hour, giving 4*6 candles; or 5*15 candles per cubic 

 foot per hour. — J. Chem. Soc., xlvii, 200, April, 1885. g. f. b. 



7. On Toughened Filter-papers. — Francis has observed that 

 filter paper is remarkably toughened by the action of nitric acid, 

 the product being pervious to liquids and quite different from 

 pai'chment paper made with sulphuric acid. By immersing the 

 paper in, or even by moistening it with, nitric acid of density 

 1*42 and subsequent washing, the result is attained. The tough- 

 ened paper can be used like ordinary paper, filtration being but 

 little retarded. It may be rubbed without injury, like a piece of 

 cloth. To compare its strength with that of ordinary paper, a 

 strip of Swedish paper 25mm. wide was made into a loop and 

 the ends held in a vertical clamp. A glass rod was passed 

 through the loop and from its ends a scale pan was suspended. 

 The paper after wetting broke with a weight of 100 to 150 

 grams, while the same paper after the above toughening treat- 

 ment supported 1*5 kilograms. Filters of this paper are very 

 useful with the filter pump, the apex only being toughened. 

 When treated the paper contracts slightly, filters 11*5 cm. in 

 diameter being diminished to 10 4 cm. The ash was reduced 

 from 0*0026 to 0*0011 gram. The treated paper contains no 

 nitrogen, and it suffers only a slight decrease of weight. — J. 

 Chem. Soc, xlvii, 183, April, 1885. G. f. b. 



8. On a Crystallized Trieupric sulphate. — The basic copper 

 sulphates hitherto known have been in general amorphous pow- 

 ders of doubtful purity. Shenstone has now prepared a crystal- 

 line basic copper sulphate artificially. In the course of experiments 

 on the solubility of salts in water at high temperatures, he ob- 

 served in the tubes in which copper sulphate and water had been 

 heated deposits of bright green crystals. By heating the crys- 

 tals of ordinary copper sulphate CnS0 4 (H 2 0) B at about 200° for a 

 few hours in tubes containing a few grams of the salt, he was 



