May 25, 1871] 
follow the English authorities, as they follow their great 
master, Hume. But in giving final expression to the 
relation between the two series of “events,” psychical 
and physical, shown by the analysis to be involved in the 
varied phenomena of intelligence, he is more strictly 
original ; or, at least, his view is stated with peculiar 
neatness and force. How shall sensation, whether in the 
“crude form or in the intellectual condition of the image 
or in the elemental state, be conceived as joined to some- 
thing so disparate as a molecular movement in nerve: 
that is the difficulty. Tosay that what we have united is 
rather an idea of sensation had by (or, in the case of the 
ultimate psychical element, conforming to the type had 
by) direct personal consciousness, and an idea of nerve 
got indirectly by way of external sense, though this is 
philosophically true, touches the difficulty without removing 
it; for the two ideas are still irreducible to each other. 
But it may then more readily be suspected that the 
“events” are not two, but one, with two permanently 
distinct faces to cognition ; and this, in M. Taine’s view, 
is the final outcome of the analytic, though as regards the 
duality he hints at a possible reduction in his second part. 
Meanwhile, taking the physical aspect as secondary and 
the sign of a properly mental event, he seeks to illustrate 
the view and to enforce his theory of universal corre- 
spondence by a remarkable analogy. He supposes an 
original text with an interlinear translation ; the trans- 
lation plain and legible at the outset, but becoming con- 
fused farther on, and before the end no longer to be made 
out ; on the other hand, the text very clear at the last but 
fainter higher up, and about the beginning not to be traced 
at all. The writing may represent nature ; clear text and 
undecipherable translation mark the states of full intel- 
lectual consciousness so vaguely referred, at least in detail, 
to the complex of the brain ; faint text and translation not 
too plain mark the cruder mental events referred to less 
but still highly complicated centres ; finally, visible trans- 
lation and blank instead of text mark the well-ascertained 
physiological phenomenon of reflex action, for which it is 
as legitimate, if not necessary, to suppose a psychical 
obverse, albeit unconscious, as it is to assume for highest 
consciousness a physical correspondence in_ brain- 
processes eluding our finest observation. 
The analogy is instructively worked out further by M. 
Taine ; but enough forthe present. Another time we may 
better estimate the value of parts of his analysis, when con- 
sidering how, from the materials it affords, he is able to 
build up the edifice of human knowledge. 
G, CROOM ROBERTSON 

A STORM-ATLAS FOR NORWAY 
Storm Atlas of the Meteorelogical Institute of Norway. 
(H. Mohn.) 
A KNOWLEDGE of the laws which regulate the 
progress of storms would be of comparatively little 
practical interest without the telegraph, but, since the 
speed of electricity outstrips that of wind} the information 
by telegraph that a storm has appeared at an outpost may 
be of great importance to a maritime country like our 
own, provided we know the path which the storm is likely 
to pursue, 
NATURE 

63 

Of late years practical meteorologists have devoted a 
great deal of attention to this branch of their subject, 
and the memoir before us is not the least interesting of 
the various contributions which have been made. It is 
unnecessary to enter into the details of M. Mohn’s obser- 
vational system; let us rather invite attention to the 
general conclusions at which he arrives. 
“Barometric maxima,” he tells us, “ often remain during 
a considerable period over the places where they have 
been formed, while, on the other hand, barometric minima 
are almost always in motion over the surface of the earth, 
transporting themselves (in Europe) almost always 
towards the east.” He further finds that the barometric 
minima represented in his charts have their greatest 
velocity of motion before they arrive at the west coast of 
Europe, and a smaller velocity when they pass by Scandi- 
navia; in Russia the velocity is again greater. 
As regards the component of the movement which leads 
the centres towards the east, he finds a greater regularity 
exhibited, inasmuch as this component diminishes conti- 
nuously as the minima move from the sea towards the 
interior of the continent. The curved paths of these 
minima are at north Europe sometimes very regular and 
sometimes very sinuous; in general they are concave 
towards the south. The mean movement in the direction 
of the meridian is towards the north in the Atlantic ; 
towards the south, but feebly, in Scandinavia ; and more 
strongly towards the south in Russia; in this latter 
country they appear to lose themselves, 
Let us now invite attention to the following remarks 
of the author with regard to vapour :—“ Vapour tension 
is an element of which the importance for the theory of 
tempests was not so evident to me until I had commenced 
the construction of these charts. . . . Charts 
giving the relative humidity are without any value, nor do 
they present any trace of that continuity which shows 
itself so strikingly in the charts of vapour tension.” Fur- 
ther on he says :—“I have frequently remarked in this 
memoir that watery vapour is one of the most important 
elements in studying the movement of air ; it is therefore 
much to be desired that the publication of meteorological 
observations should embrace vapour tensions (which is 
not always the case), and if only one element can be given, 
let it be rather that than the relative humidity. 
Charts representing the distribution of the vapour of 
water over the surface of the earth analogous to the tem- 
perature charts of M. Dove or the isobaric charts of Mr. 
Buchan would be of the greatest possible utility.” 
It may not be out of place to make a few remarks upon 
these observations of M. Mohn. Meteorologists have 
been in the habit of discussing in two ways the state of 
the air with regard to vapour. They have in the 
first place studied the vapour tension present in 
the atmosphere, and secondly, they have studied the 
relative humidity, or what M. Mohn calls “/é¢at hygro- 
métrigue.” This latter element, representing the propor- 
tion between the vapour actually contained in the air and 
the full amount due to the present temperature, is an 
element that varies very greatly with the temperature, 
and is, therefore, of comparatively little use in meteoro- 
logical researches, 
Besides these two elements, the author of this review 
has suggested the Aygrometric quality of the air as a 
