August 22, 1907] 



NA TURJi 



41 1 



The reasoning here appears to be scarcely conclusive ; 

 There is some unexpressed assumption as to the natur'- 

 of the action between aether and matter; and that 

 whirls (bv which some kind of vortex motion appears 

 to be meant) would necessarily result wants demon- 

 stration. These whirls have, at a later sfajje in th<- 

 book, to do duty in explaining- terrestrial magnetism 

 as well as the relations of the heavenly bodies and 

 their gravitational attraction. Again, p. ii : — 



" It has long ago been proved that in jether all 1 

 bodies fall with equal rapidity towards the centre of 

 the »arth, and it may, therefore, be reasonably ! 

 assumed that all atoms which disnlace equal amounts ! 

 of ather have equal weight. There are, however, I 

 many and convincing reasons for believing that the 

 atoms of different chemical elements have widely I 

 different weights." "The explanatiort, then, which j 

 suggests itself as acrounfinf for this difTerenre, accord- ' 

 ing to the present theory, is the very simple one that 

 the heavier atom is of larger bulk, and displaces more 

 asther than the smaller atom. From this it follows 

 that the sizes of chemical atoms are in the same ratio 

 as their weights." ' 



From this, Gay-Lussac\ law and Avogadro's law are 

 derived. Boyle's law and the deviationf from it are 

 treated much in the same fashion, and the author 

 then finds it necessan.- to introduce another factor \ 

 (p. 15), the shape of the molecules. A table of the \ 

 chemical elements arranged with their atomic weights I 

 in ascending order of magnitude (the character — gas, 

 liquid or solid— -of each Ix-ing stated) is given. Argu- 

 ing from this table, the statement is made : — 



" It must hence be admitted that elements with a 

 low atomic weight are much more disposed to be 

 gaseous than thos'- of higher atomic weight, at 

 ordinary temperature and pressure- This quite accords 

 with the theory that their ultimate particles are 

 smaller than those of elements with higher atoinic 

 weights. " 



The diflRcult>- that there are so many solid elements 

 of low atomic weight is got over by invoking the 

 influence of shape. For example, the liquidity of 

 mercury is explained by supposing the atom of mercury 

 to be spherical. A curious reader micht wish to know 

 the approximate shapes of the atoms of argon or 

 lithium, but on this point the author is silent, .■\fter 

 some pages of the same kind of reasoning, two laws 

 are enunciated : — 



(i) " The condition of chemical elements or of chem- 

 ical compounds, at similar temperature and pressure 

 and under similar conditions generally, depends on 

 their atomic or molecular weights fthat is, on the size 

 of their atoms or molecules* and on the shape of their 

 atoms or molecules." (21 "The relative chemical 

 activity and chemical properties of chemical elements 

 or chemical compounds, at similar temperature and 

 pressure and under similar conditions generally, de- 

 pends on their atomic or molecular weights and on 

 the shape of their atoms or molecules." 



The term law appears to be used here in a stanewhat 

 unusual sense, as these statements do not constitute 

 laws ; to make them such, die laws of dependence 

 should be known. Another good example of the 

 author's mode of reasoning is to be found on pp. 53, 

 54, where the fact that glass is transparent to light 

 >'0. 1973, VOL. 76] 



but opaque to heat is explained by the peculiarities of 

 the interstices filled with a-ther in the case of glass, 

 the nature of these being inferred from the way in 

 which glass fractures. 



It will appear from ihe-e examples of the author's 

 treatment that his theory cannot even make good a 

 claim to be considered a reasonable working model. 

 A great number, however, of the better known physical 

 and chemical phenomena are brought together, and 

 on this account the book may perhaps prove interesting 

 to readers who have not sufficient leisure or inclin- 

 ation for the perusal of treatises and memoirs that have 

 greater pretensions to scientific accuracj-. 



FOUNDRY PHACTICE. 

 General Foundry Practice. By A. McVVilliam and 

 P. Longmuir. Pp. vii + 383. (London : Charles 

 Griffin and Co., Ltd., 1907.) Price isx. net. 



THE opinion is generally held among metal- 

 lurgists that with the rapid progress nvide of 

 recent years in Great Britain in the metallurgy of 

 iron the foundry has hardly kept pace. Mr. 

 McWilliam and Mr, Longmuir take a more optimistic 

 view, and fxriieve that advances have been, and are 

 being, made of a magnitude commensurate with 

 those of other industries. Certainly signs of pro- 

 gress are apparent in this important branch of metal- 

 lurgy. The empirical method of charging the cupoLi 

 is giving place to the system of weighing all 

 materials in proportions determined by the chemist. 

 High-temfx*rature measurement is being practised in 

 the core and drying stove. The field for machine 

 moulding is extending. Permanent moulds made of 

 carbon or similar material are being tried; and the 

 founder is just realising the fact that micrographic 

 analysis has a commercial value. In short, in all 

 branches of his work he is showing a praiseworthy 

 desire to emerge from the slipshod ways of the past. 

 The literature of the subject has, however, remained 

 meagre, and not of a strikingly scientific character. 

 Scattered through the pages of the Journal of tiv; 

 Iron and Steel Institute and of the iron trade 

 journals there is much information of (jermanent 

 value; but the sptxial treatierrs on the subject are 

 mostlv of an elementary character. The ^^xhaustive 

 work by Mr. McWilliam and Mr. [xmgmuir may 

 therefore fairly be regard'^ as marking an epoch 

 in the history of iron founding, and should help 

 greatly in effecting a clear understanding of the sub- 

 ject. The authors possess special qualifications for 

 the work they have undertaken. Mr. I^ongmuir has 

 held the position of foundry foreman, and is a 

 Carnegie research medallist of the Iron and Steel 

 Institute, »-hJle Mr. McWilliam, a distinguished 

 Associate of the Royal School of Mines, has at the 

 University of Sheffield had ample opportunity of 

 ascertaining the needs of students. They have there- 

 fore been able to draw upon experience gained under 

 normal foundry- conditions and under the conditions 

 of experimental laboratories, and the operations they 

 describe have >>'-<-'• rj^-rs^jnally followed. 



