400 H. W. Dove on Rain in the Temperate Zone. 
change does not extend across the Himalayah range, and that 
over these mountains another meteorological system begins; he 
extends this zone, making it to embrace the whole earth, beyond 
America to the Sandwich Islands. 
In 18311 wrote as follows, opposing the notion that the south- 
west monsoons are winds descending from above: (vide Pogg. 
Ann., xxi, 177,) “all observation seems to show that between 
the southwest winds on the outer limits of the monsoon and 
those in the Indian Ocean, the following differences exist: the 
ormer appear in winter, the latter in summer; those in a south- 
erly direction are bordered by northeast winds, the others by 
southeast winds.” According to Halley’s theory, as followed by 
Mushenbroeck, Capper, Hube and Horsburg, these lower cur- 
rents do not come from above downward, as conjectured by Hal- 
ley, and proved by v. Buch. 
The question why the appearance in the Atlantic is so differ- 
ent from that in the Indian Ocean, I then tried to answer by the 
theory that the high lands of Asia intercepted the passage of north- 
erly currents, and thus no other current met the monsoon as it 
hurried up from below, except the mass of air between the neigh- 
borhood of the calms and those high mountains. With the ap- 
proach of the sun, the mass of air moving in the perpendicular 
circuit diminishes, till at last it no longer opposes the southeast 
wind and takes quite an opposite direction. In the explanations 
of a phenomenon, all views may be divided into two classes, ac- 
tual explanations, and evasions of nature. Of the Jatter kind 
was my former explanation, and so conscious was I of its weak- 
with reference to the theory of monsoons, pointin 
rents lay far towards the north. 
Although the universality of the phenomenon of periodic di- 
minished pressure was so clear that Kupffer in the edition of 
Asiatic Observations published in 1841, said: “one has only to 
look at the results of the observations contained in this volume 
to find a complete confirmation of all that M. Dove has advanc- 
ed on this point,” yet I then first proved decidedly that the 
southwest monsoons are the lower tradewind, which rushes to- 
ward the point of disturbance to fill up the void that owing:t0 
the increasing temperature here in inner Asia the diminished 
moisture was not sufficient to occupy. The proofs are indirect 
indeed, but all who have occupied themselves with meteorolog!- 
eal observations know that hardly any problem of this nature 
can be directly proved, and that whoever has to do with the 
winds must follow the vane. 
