Magnetic and Electric Saturation Values. 351 



the limits +a would be equally likely, and that is what the 

 frequency graph described above would imply. If then we 

 suppose that errors are not of mysterious character, sui generis, 

 but are simply the mass of numberless neglected disturbances, 

 each occurring according to regular law and order of its 

 own, it is seen that we obtain the approximation to Gauss's law 

 which is necessary to begin with, by the operation of neglecting 

 the circumstances and order of their origin, and scheduling 

 merely in sequence of magnitude the number of times that each 

 particular value occurs. It is this operation that is the signi- 

 ficant act which effaces the individuality of the contributing 

 elements and permits us to obtain, apparently from nothing, 

 the law of Gauss ; for if we go on repeating it for more and 

 more sources of error, we obtain the law with greater and 

 greater purity. This is the view of the actual logical basis 

 of the Error Law which I endeavoured to convey in my 

 paper. It does not escape, of course, the difficulties of con- 

 vergence which present themselves in Laplace's theorem, 

 for these are inherent, and in a strict sense, fatal to absolute 

 generality. Nor does it oust any other proof. But I offer 

 it as a view by which we can see the law coming into existence, 

 which I submit the other forms of proof one and all fail to 

 supply. 



XXXVIII. On the Calculation of Magnetic and Electric 

 Saturation Values. By J. R,. Ashwoeth, D.Sc* 



THE principal object of this paper is to show how it 

 is possible to calculate from two well-known constants 

 the limiting value of the magnetic intensity of a magnetic 

 substance for which Curie's law holds good, and by the same 

 reasoning to estimate the limiting current density which a 

 conductor can carry in the case of those metals in which 

 the resistivity is directly proportional to the absolute 

 temperature. 



Magnetic Intensity. 



In genera], paramagnetic substances at all temperatures, 

 and ferromagnetic bodies above their critical temperatures, 

 obey a simple law which is analogous to the gas law. 



* Communicated by the Author. 



