586 



SCIENTIFIC RECORD FOR 1883. 



five flats, five or six sharps) the best plaii is to tune it in twelve mathe- 

 matically equal semitones. (Nature, Jauuary, 1883, xxvn, 240.) 



Huggins has communicated to the Royal Society a paper on the 

 function of the sound-post of the violin, iu which he comes to the con- 

 clusion that this sound-post is more than a prop, and that besides its 

 other functions it does transmit vibrations to the back in addition to 

 those which are conveyed through the sides. He has also investigated 

 the proportional thickness of the strings in use as compared with that 

 required by theory. (Nature, July, 1883, xxvm, 259.) 



HEAT. 



1. Production of Heat; Thermometry. 



Ancelin has patented the use of sodium acetate as a heating agent, 

 the object being to use its latent heat of fusion, which is very high, for 

 the purpose of giving out heat in the interior of railway carriages, etc. 

 He finds that the heat given out by sodium acetate is four times greater 

 than that given out by water. A railway warming pan, containing 

 eleven liters of water, in passing from 80° C. to 40° evolves 440 calories, 

 while the same pan, containing about 50 kilograms of sodium acetate, 

 evolves in passing from 80° to 40° 1,731 calories. Moreover, the ex- 

 penditure of heat required to reverse the operation is much less in the 

 case of the acetate. To heat the pan of water, containing 11 liters, 

 from 10° to 90° four times, 3,520 calories are required ; while for the 

 same volume of acetate only 1,987 calories are needed, a saving of 1,500 

 calories. Again, in the case of water at 90°, four healings return only 

 1,760 calories, or 50 per cent., while iu the case of the acetate the un- 

 utilized heat amounts only to 256 calories, or 12 per cent, of the quantity 

 stored. The water cools much more rapidly. (Nature, February, 1883, 

 xxvn, 344.) 



Fischer has given the following values for the amounts of heat (calo- 

 ries) of water vapor (kilograms) and of carbon dioxide (cubic meters) 

 given off in the various illuminating processes in ordinary use. These 

 amounts are all calculated for a light of one hundred candles burning 

 for one hour. 



Illuminating processes. 



Electric lamp (arc) 



Electric lamp (incandescent) 



Gas ( Argancl burner) 



Lamp, petroleum (flat flame) 



Lamp, colza oil 



Candle (paraffine) 



Candle (tallow) 



Heat. 



57-158 



290-536 



4860 



7200 



6800 

 9200 

 9700 



The hygienic superiority of the electric light is clearly shown by these 

 figures. (J. Soc. Tel. Eng., xn, 625-, Nature, July, 1883, xxvm, 281.) 



