92 
[February, 
Analyses of Books. 
and it is pointed out in a note that — according to the recent 
determinations of Nilson and Petterson — the melting-point of 
beryllium chloride is from ioo° to 150° C. lower than the temper- 
ature ass'gned by Carnelley. Further developments of the 
periodic law, due to the researches of Hartley and Laurie, are 
also mentioned. The former chemist shows that the ultra-violet 
specftra of elements of the same series exhibit fairly-marked 
analogies in their general character. Still the specftra hitherto 
obtained do not warrant either the assertion or the denial of nu- 
merical relations existing between the different groups of lines, 
sufficient to establish a definite periodic connection between the 
atomic weights of the elements and the wave-lengths of the 
lines in the elementary specftra. 
Laurie shows that there exists a distinct periodic connection 
between the atomic weights and the combining heats of the ele- 
ments with chlorine, bromine, and iodine. 
The author closes this chapter with the remark that it is inte- 
resting to observe in the periodic law “ the survival, — perhaps 
rather the resurrection, — in a modified and more precise form, of 
the old conception of the element as an essence or principle 
capable of impressing on all substances into which it entered 
properties sufficiently definite to mark off all these substances 
from all others which did not contain this principle.” 
The author observes, concerning the “nascent” state and 
“ nascent” action, that this expression has been at once helpful 
and hurtful. “ By classing under a common head many pheno- 
mena which might otherwise have been lost in the vast mass of 
facts with which the science has to deal it has done good service. 
On the other hand, on the principle that 
1 Wo Begriffe fehien 
Da stellt zur rechten zeit ein Wo;t sich ein,’ 
its use has tended to prevent investigation.” 
In treating of chemical change and its conditions the author 
calls attention to the influence of mass. He insists, in passing, 
on “the importance of considering the relative masses of the 
reaching bodies in all processes of chemical change, and to 
remind the student that this facftor is almost universally ignored 
in our ordinary chemical equations.” 
The questions of the origin of the elements, of their possible 
decomposition or their mutual transformation, are not taken into 
account. The author — not without grounds — doubtless holds 
that such speculations are metachemical rather than chemical, 
and that the time for their definite solution cannot be said to 
have arrived. 
In examining Mr. Muir’s work we have been insensibly led, 
instead of giving a connected analysis of its teachings, to call 
attention to his views on a number of the most important sub- 
