34 abstracts: physics 



PHYSICS. — Note on the temperature scale between 100° and 500° C. 

 C. W. Waidner and G. K. Burgess, Bulletin Bureau of Standards, 

 7: 1-9. 1911. 



By means of resistance thermometers reading to an accuracy of 1 in 

 100,000 and calibrated 1 at the ice, steam, and sulphur-boiling points, 

 using the Callendar equation, the nitrogen constant volume tempera- 

 ture scale in the interval 100° to 500° C. is found to be represented to 

 better than 0.1° C. by the following freezing and boiling points: 



Freezing Boiling 



Tin 231.9 Naphthaline 218.0 



Cadmium 321.0 Benzophenone 306.0 



Zinc 419 4 Sulphur 444 7 



G. K. B. 



PHYSICS. — On the constancy of the sulphur boiling point. C. W. 

 Waidner and G. K. Burgess. Bulletin Bureau of Standards, 7: 

 127-130. 1911. 



Thermocouples of platinum and other metals such as are used in high 

 temperature measurements often give results in the sulphur boiling 

 apparatus discordant by 1° C. or more. 2 By means of platinum-rhodium 

 thermocouples free from inhomogeneity and notably with one of only 

 0.1 mm. diameter, as well as by means of a resistance thermometer of 

 very short coil, less than 9 mm. in length and of 13.1 ohms resistance 

 taking only 0.006 amperes measuring current, it is shown that the point 

 to point variation in temperature within the usual form (loc. cit.) of 

 sulphur boiling apparatus is less than 0.05° C. The sulphur boiling- 

 point appears to be the most exactly defined, the most certainly repro- 

 ducible, and the most constant yet studied, of all the fixed temperatures 

 given by the chemical elements. G. K. B. 



PHYSICS. — A new form of direct-reading candle-power scale and recording 

 device for precision photometers. G. W. Middlekauff. Bulletin 

 Bureau of Standards. 7: 11-44. 1911. 



In precision photometry it is necessary to take a large number of 

 readings, which, with the subsequent calculations for candle-power, are 

 not only fatiguing but introduce the possibility of error, especially when 

 the observer has both to read the photometer and record the settings 



1 Bulletin Bureau of Standards, 6. 149-230. 1910. 



2 Ibid., 6. 149-230. 1910. 



