TRANSACTIONS OF SECTION A. 655 



In any such formula the constants must have values neither very great nor 

 very small. This is tested and found to be true. On attempting to carry out the 

 mathematical calculations suggested, the radiation is found to vary as the tempera- 

 ture ; a quite impossible result. Various modifications of the nature of the 

 hypothetical gas selected are considered and dismissed as unsatisfactory. 



The truth of the second law of thermodynamics is made to depend on the con- 

 stancy of the ionic charges. This indicates that the constancy of the charge i» 

 due to some fundamental property of the ether. It seems probable that a com- 

 plete solution of the problem requires a complete theory of matter and electricity. 



WEBNESDAY, SEPTEMBER 12. 

 The following Report and Papers were read : — 



1. Report on Electrical Staiidards. — See Reports, p. 53. 



2. A Form oj Wheatstone's Bridge. By E. H. Griffiths, F.B.S. 



3. iVo/e on an Lyiproved Standard Hcsiff/ance Coil. 

 By R. S. Whipple. See Reports, p. 55. 



•1. A Preliminary Research on Explosive Gaseous Mixttires.^ 

 By J. E. Petavel. 



Objects of the Eesetirch.—The primary object of the present research is to 

 extend the work originally done by Bunsen at atmospheric pressures to initial 

 pressures of one or two hundred atmospheres. 



Both the maximum pressure of the explosion and the rate of change of the 

 pressure are recorded. A long series of experiments, the result of which will 

 shortly be published, having proved the very high thermal conductivity of com- 

 pressed gases, it was important to obtain some further data with regard to the 

 thermal properties of gases at the highest temperatures and pressures. It is alsa 

 desirable that some further information with regard to the phenomena of dissocia- 

 tion at very high pressures should be obtained. 



Finally, it is hoped that, from a practical point of view, the results will be of 

 use as a contribution to the knowledge of thermodynamics. 



In all heat engines the efficiency is greatly increased by the use of a wicler 

 temperature interval and higher pressures. Whereas mechanical difficulties, which, 

 up to recently, had hindered progress in this direction, are gradually being over- 

 come, the theoretical side of the question has not received all the attention it 

 merits. 



The Apparatus.— In order to gain some information with regard to the effisct 

 of the surface of the enclosure, three distinct enclosures are used : — 



1° A spherical enclosure of 500 c.c. capacity (about 4 in. diameter). 

 2° A cyhndrical enclosure, 27 in. long, also of 500 c.c. capacity. 

 3° A spherical enclosure of about 10,000 c.c. capacity. 



The first two enclosures are calculated to withstand pressures up to two thousand 

 atmospheres ; the third, pressures up to two hundred atmospheres. 



' The experiments have been carried out at the Davy-Faraday Laboratory of the 

 Royal Institution. Part of the apparatus was provided by the Laboratory, the 

 remainder being purchased with the funds awarded for this purpose by the Govern- 

 ment Grant Committee of the Royal Society. 



