ABSTEACTS: PHYSICS 87 



PHYSICS. — Easy calorimetric methods of high precision. Walter P. 

 White. J. Am. Chem. Soc, 36: 2313-2333. 1914. 



In the calorimetric method of mixtures, a precision approaching or 

 reaching 0.1 per mille, though somewhat unusual, is often desirable, 

 and is ordinarily not difficult to attain with appropriate apparatus. 

 Its attainment is especially easy with a two-calorimeter installation, 

 which secures the convenience and high precision of differential thermo- 

 electric temperature measurement. This is the only advantage of the 

 two-calorimeter arrangement; the diminution of heat-loss error, often 

 counted an advantage, turns out upon examination to be largely illu- 

 sory. By abandoning the twin calorimeters previously used to get this 

 supposed advantage, and using for the comparison calorimeter a vacuum- 

 jacketed flask, there is a gain in convenience and precision. A special 

 thermo-element coml^ination renders the necessary temperature obser- 

 vations as simple as with the twin arrangement. A completely inclos- 

 ing jacket of uniform temperature is necessary for this method, but this 

 is no loss, for such a jacket proves to be necessary for highest precision 

 with any other method. This method is quite as effective with two 

 jackets, one around each calorimeter, and therefore with adiabatic 

 methods. 



Efficient complete jackets can be very easily realized according to 

 several methods, which are described. 



As compared with others, the present method is specially advantage- 

 ous for observations of great absolute precision and wherever it is de- 

 sirable to secure the advantages which the thermo-electric system pos- 

 sesses in the way of rapidity and of facility in making varied observa- 

 tions. W. P. W. 



PHYSICS. — A significant instance of galvanometer instahility. Walter 

 P. White. Phys. Rev. (2), 3: 491-492. 1914. 

 A radial-field moving coil galvanometer, very free from ordinary tre- 

 mors, was much deflected by various shocks occurring within the build- 

 ing, and this effect disappeared whenever the supporting shelf was fas- 

 tened to the wall with sufficient firmness. Apparently, a slight tipping 

 of the shelf was to blame. At any rate, if there had also been any 

 visible tremors of the galvanometer coil, these would have been sup- 

 posed to be responsible for the trouble. It follows that in other cases 

 where tremors are present, and are supposed to cause troublesome de- 

 flections, the real trouble may be due to some other, more easily remova- 

 ble cause. W. P. W. 



