REVIEWS. 
307 
tlie south-west of their origin. It is found that the barometer ranges lower 
than usual on the part of the hay in which they originate. This depression 
takes place during a slight general fall of the barometer over the bay, such 
as occurs normally at intervals of a few days to a fortnight, at all seasons of 
the year. The formation of the cyclonic vortex appears to be preceded by a 
general recurvature of the southerly current around the place of low baro- 
meter. When the vortex forms the barometer falls still lower over the 
vortex and continues to fall while the cyclone gathers strength. The re- 
curved south-westerly current being the chief feeder of the cyclone, and the 
vortex being formed more or less towards its western limit, the weather to 
the east and north-east of a cyclone is more stormy than that to the west and 
north-west of it. In and around the cyclonic vortex there is a strong in- 
draught of the wind-currents so that their direction is spiral, not circular, 
but more nearly circular within ten or fifteen miles of the centre than at 
greater distances from it. Finally the editors say that “the cyclones do not 
in all cases (perhaps in any P) move forward steadily on their track, but one 
vortex may break up while another is forming at some distance in advance.’’ 
The duration of a central calm cannot therefore (even if its diameter be 
known) be taken as a measure of the rate of progress of the storm (the suc- 
cessive vortices being considered as one storm). 
It will be seen by the above suggestion-conclusions, if we may use such a 
term, what good work Indian meteorologists have done. Let it be an ex- 
ample for those who so energetically decry the Fitzroy weather signals, and 
decline to give us even substantial facts in their stead. Let some English 
meteorologists follow in the footsteps of their Indian brethren and give us 
on the subject of “Storm-signals” a treatise of which we may say, as we 
do honestly affirm of the one before us, that it is a model meteorological 
monograph. 
POPULAR ASTRONOMY* 
P ERHAPS the reader may say we are overdosed with lectures on Astro- 
nomy. There appears too, to be some truth in the remark, but though of 
late years the works on this branch of science have been very numerous, 
some of them have been works whose many technicalities and references to 
the higher mathematics placed them at once beyond the comprehension of 
the amateur. It is, however, the special feature of all Dr. Lardner’s books 
that they address themselves to the general public/and we may observe also 
that while they are tolerably accurate in point of fact they are written in a 
language at once terse and untechnical, and which is easily intelligible to 
those whose mathematical knowledge is of the usual elementary character. 
It happens, however, that a good deal of advance has been made in the 
several branches of science which Dr. Lardner endeavoured to popularise 
* Handbook of Astronomy, by Dionysius Lardner, D.C.L., 3rd edition. 
Edited by Edwin Dunkin, F.R.A.S. London: James Walton, 1867. 
