October. 1913. 



KNOWLEDGE. 



373 



Newcomb. — " The Stars : A Study of the Universe." 

 1902. 



" A very remarkable case is that of Zeta Orionis. 

 It has a minute companion at a distance of 2" -5. 

 Were it a model of the Sun, a companion at this 

 apparent distance should perform its revolution in 

 fourteen years, But, as a matter of fact, the motion 

 is so slow that even now, after fifty years of observa- 

 tion, it cannot be determined with any precision. 

 It is probably less than 0"- 1 in a year. The number 

 expressing the comparison of the density and surface 

 brilliancy of this star with those of the Sun is 

 probably less than 0-0001. The general conclusion 

 to be drawn is obvious. The stars in general are not 

 models of our Sun." (Page 200.) 

 Newcomb. — " Popular Astronomy," 1882. 



" Then a mathematical computation of the attrac- 

 tive power exerted by such a system of masses 

 (five hundred million sun-masses) shows that a body 

 falling from an infinite distance to the centre of the 

 system would acquire a velocity of twenty-five miles 

 a second." (Page 501.) 



This calculation does not seem to be correct, but 

 it serves to show how impossible it is for the potential 

 energy of a nebula composed of nebulium, helium 

 and hydrogen to be changed by gravitation into the 

 radio-active and other atomic energies of heavy 

 atoms. The velocity with which a small mass 

 falling from rest at an infinite distance would strike 

 the Sun is three hundred and eighty miles a second. 

 This means that a gram falling into the Sun would 

 generate forty-four thousand eight hundred and 

 forty-four calories ; this is but one five hundred 

 thousandth of that evolved by radium. 



Perry.— "The Life of a Star." Nature, 1899, 

 July 13th. 

 "Assumptions like those of Homar Lane and 

 Ritter may lead to results which are altogether 

 wrong. . . . Homar Lane, Lord Kelvin, Ritter, 

 and all people who have tried to make exact calcula- 

 tions, have assumed that the stuff of which a star is 

 composed behaves as a perfect gas in a state of 

 convective equilibrum. . . . But if we apply 

 our results to the Sun we find that at its centre there 

 is a density thirty-three, that is, fifty per cent, 

 greater than the ordinary density of platinum. It 

 seems to me that speculation on this basis of 

 perfectly gaseous stuff ought to cease when the 

 density of the gas at the centre of the star 

 approaches 0.1 or one-tenth of the density of 

 ordinary water in the laboratory. . . It seems to 

 me that if a mass of this kind of gas (in which H the 

 ratio of its specific heats =1§) gravitates by itself 

 from an infinite distance, it retains all its energy. 

 But such gas must surely be imagined to be radiating 

 heat, as it is not at zero temperature. Where can it 

 get such heat ? I come to the conclusion that there 

 must be atomic energy available somehow in it. 

 I say that no substance for which 8 =1$ can behave 

 as a perfect gas." 



Kelvin's remarks on and his endorsement of 

 Professor Perry's conclusions will be found in 

 Nature, 1907, February 14th. 



Ramsay. " Elements and Electrons, 1912." 



" Cordite, the explosive powder used for our 

 artillery, evolves 1,253 calories per gram. . . 

 Radium, 2,800,000,000 calories." 



CORRESPONDENCE. 



"THE ORIGIN OF LIFE." 

 To the Editors of " Knowledge." 



Sirs, — I have seen Mr. H. Stanley Redgrove's article in the 

 August number of " Knowledge " in which he refers to a 

 "nine days' wonder" produced by my experiments on the 

 action of radium salts on sterilised organic media, such as 

 gelatin bouillon used for the cultivation of bacteria. He adds 

 that Mr. Soddy showed the effects were of a purely chemical 

 nature. I was not aware that Mr. Soddy had made any 

 experiments upon the subject ; nor do I believe that unlike the 

 effects produced by barium, strontium, and lead salts, the 

 results due to radium are of a purely chemical nature. 



The effects are on the whole physical rather than chemical 

 as I have repeatedly pointed out, and as Sir William Ramsay 

 was good enough to explain they might have been expected to 

 be. My own views upon the subject were put forward at 

 length in my article in the Fortnightly Review, September, 



1905, and in my book on the "Origin of Life" published in 



1906, of both of which Mr. Redgrove is apparently unaware. If 

 these experiments remain a nine years' wonder I throe not, but 

 I venture to deny, considering the prolonged discussion to 

 which they have given rise, and are likely yet to give rise to when 

 more fully understood, that they were a nine days' wonder if 

 indeed they can be said to be a wonder at all. 



BRITISH MEASURES NEARLY HYDROMETRIC. 



To the Editors of " Knowledge." 

 Sirs, — It is not, perhaps, generally known that our British 

 system of weights and measures is very nearly hydrometric, 

 that is, having a simple relation between the measures of 

 length and weight through the medium of water. If we 

 suppose that the gallon is reduced by the small amount of 

 three one-thousandth parts, we have the following interesting 

 and useful relation : 



Sixty-four cubic feet = four hundred gallons. 

 We may visualise this by picturing a cube which measures 

 four feet in each direction and therefore contains 4X4X4, or 

 sixty-four cubic feet. 



Now by law a gallon of water weighs ten pounds; and to 

 preserve this relation we must suppose the pound to be 

 reduced by the same small amount as the gallon. If this be 

 done, and if for convenience we call our four-foot cube a 

 " vol," we shall have 

 One vol of water weighs two tons (four thousand pounds). 

 An easy deduction from this is 



One cubic foot of water weighs one thousand ounces 

 and from this again we have 



Tn-foot cube of water weighs one ounce. 



IMMO S. ALLEN. 



Weybridge. 



JOHN BUTLER BURKE. 



London Institution, 



Finsbury Circus, E.C. 



