226 



Mr. S. H. Burbury on the Law of 



six times as well as the other. The curves have been drawn 

 by an approximate method which depends on the fact that 

 near each angular point A, 0, the equation which tranforms 

 the kite-shaped figure of fig. 3 into the square of fig. 2 takes 

 the form z = Az n . The accuracy of the diagrams will therefore 

 be least near the centre of each square ABCD, where the 

 position of an equipotential line may be in error by 10 per cent, 

 of its distance from the next one. 



Professor Lamb has pointed out to me that by superposing 

 a second flux, the direction of which is at right angles to the 

 first, On the first, a flux with stream and equipotential lines 

 through the centres of the squares parallel to their sides is 

 obtained. The conductivity of the medium for this flux will 

 be readily seen to be given again by the formula 



The equipotential lines (or the stream-lines) for a strip of the 

 medium, when one constituent conducts six times as well as 

 the other, are shown in fig. 6. 



Fig. (3. 



Since there are four directions in the medium in which 

 the conductivity has the above value, the conductivity of the 

 medium for a flux in any direction has the same value, i. e. 

 equation (4) gives the conductivity of a compound medium in 

 the general case where the constituents are present in the form 

 of long prisms with their axes perpendicular to the planes of 

 flow. 



XVII. The Law of Partition of Kinetic Energy, 

 By S. H. Burbury*. 



LORD RAYLEIGIFS article f seems to raise the question 

 what is the enunciation of the Maxwell- Boltzmann 

 law of equal partition of energy. It cannot mean that in 

 every case in which a number of particles of unequal masses 

 are in stationary motion each particle has the same mean 

 * Communicated by the Author. f Supra, p. 98. 



