6Q4 
TNI? TROPICAL AGRICULTURIST. [April i, 1890. 
north-east, in the direction of Iceland, in which case 
they are not felt on our coasts, and hence the frequent 
failure of these American warnings. 
It is the region of low pressure in the North 
Atlantic that is the special field of these storms. As 
they pass across it' they produce considerable modi- 
fications in the distribution of pressure, but some of 
its main features remain outstanding. Thus there is 
always a belt of high barometer between storm region 
and the trade-winds, and in the winter there is almost 
always a reign of high baromet3r over North America, 
and another over Europe, and Asia, however much 
they may shift their places, and be temporarily en- 
croached 011 by the great storm eddies. 
These regions of high pressure are the places where 
the winds descend, and, as I mentioned in the earlier 
part of this lecture, these winds are dry, and generally 
accompany fine weather. On the contrary, the eddies, 
where the air ascends, are damp and stormy, and es- 
pecially that part of the eddy that is fed by the south- 
west winds that have swept the Atlantic since their 
descent, and so have become charged with vapour. 
And now we are prepared to understand why east, 
and especially north-east winds are generally so dry. 
Th> y are air that has descended in the area of high 
barometer that, especially in the winter and spring, 
lies over Europe and Asia, and has subsequently swept 
the cold land-surface, which does not furnish much 
vapour, and therefore they reach us as dry cold winds. 
To begin with, the air comes from a considerable 
height in the atmosphere, and in ascending to that 
height in some other part of the world, it must have 
got rid of most of its vapour in the way that has 
been already explained. In descending to the earth's 
level it must, of course, have been dynamically heated 
by the compression it has undergone, but all or 
nearly all this heat has been got rid of by radiation 
into free space on the cold plains and under the clear 
frosty skies of Northern Asia and Northern Europe, 
and it then blows outwards from this reign of high 
barometer over the laud, towards the warmer region 
of low barometer on the North Atlantic Ocean. 
Thus we see that, in all cases, rain is produced by 
the cooling of the air, and that in nearly all, if cot 
all, this cooling is produced by the expansion of the 
air in ascending from lower to higher levels in the 
atmosphere, by what is termed dynamic cooling. 
Tkii last fact is not set forth so emphatically as it 
should be in some popular text-books on the subject, 
but it is an undoubted fact. It was originally sug- 
gested by Espy some forty years ago, but the truth 
is only now generally recogn zed, and it is one of the 
results which we owe to the great advance in physical 
science effected by Joule's discovery of the definite 
relation of equivalence between heat and mechanical 
work. 
•* 
Condition of Matjbitius in 1889,— The Be- 
port of the Chamber of Commerce concludes in the 
following terms : — 
In conclusion it may be briefly remarked that, as the 
Colony has been spared the scourge of cyclones for 
some years past, its agricultural condition has im- 
proved, and although the Crop which may now be snid 
to be almost gathered in will, contrary to general ex- 
pectations at its commencement, show a deficiency 
compared with that of last year, the range of pries 
for all grainy descriptions of sugar have been on the 
whole remunerative, and the general position of Agri- 
culture may be said to have gained strength during 
the year under review. On the other hand, there is 
unfnrtuuately no marked improvement to record in 
Commerce. Operations in import business have con- 
tinued to be conducted on a limited scale and at small 
pr )lit. Judgincr, however, from statistics and reports 
from other commercial centres, there are evident 
signs of a steady improvement in commerce and trade 
gen rally, and it is to be hoped that, under the guid- 
ai 0 of The Almighty, the benefits of a revival in 
(,, el <;•.•• h> re may ' oon be extended to this Colony 
also and continue throughout the remaining years of 
the century. — Mauritius Merchantfi 1 and Planters' 
fja?.elte. 
Extremes or Temperature.— Mr. 8. E. Peal writes 
us from Sibsaugor on the 8th :— We have lately 
had the thermometer so low, that it seems worthy 
of being recorded. On the 2nd and 3rd instant 
at dawn in the open air— facing the East, it 
stood at 37 deg. F. and after Sunrise, when the 
sun was visible through the fog 39} deg. In the 
sun at 2 p.m. the same thermometer rose to 132 deg. 
a range of 95 deg. and as I do not systemaiicaly 
examine the minimum or maximum I have little 
doubt it exceeded this. In the rains I have seen 
the temperature 172 in the sun, but a range of 95 
deg. is not bad in one day.— Indian Planters' Gazette. 
Pearl Fishing in Queensland. — The report of 
Mr. W. Saville-Kent, f.l.b., f.z.b., &c, Commis- 
sioner of Fisheries, on " Pearl and Pearlshell 
Fisheries of Northern Queensland," has just been 
issued from the Government Printing Office. It 
contains a general description of the fisheries, 
suggested regulations and concessions, an ac- 
count of experimental operations by Mr. Saville- 
Kent, and concludes with a summary of the 
preceding chapters. From the report it appears 
that the average annual value of the Torres 
Straits pearlshell fisheries for the past five years 
was £69.000. The report is illustrated by two 
plates.— Queenslander, March 1st. 
Ceylon Tea for Canada. — It is very satisfac- 
tory to know that apart from the Tea Company there 
are several individual planters engaged in pushing a 
tea trade in America. One of the earliest to find 
an opening for Ceylon teas in the Far West is 
Mr. Joseph Fraser of Damboolagalla, who for some 
years now, has been ab'e to place a considerable 
proportion of his crop on the Canadian market. 
That the tea gives satisfaction may be judged from 
what Mr. Fraser writes to us : — 
You will be pleased to hear that the Canada orders 
for tea continue to increase. I have to send away to 
this quarter during the next 6 weeks some 16,000 lb. 
The thanks of brother tea planters are due to Mr. 
Fraser and other gentlemen who, by finding new 
outlets for Ceylon tea, divert so much from the 
London market. 
Mining and Gemming Ordinance. — We call 
attention to the discussion on this subjeot at the 
Chamber of Commerce. When we remember that 
Sir Arthur Gordon has had experience as an Aue-- 
tralasian Governor, and that if ignorant of the 
terms adopted in the Gold Oolonits, he could so 
easily learn the policy of the Madras authorities, 
it is passing strange that he should have allowed 
himself to be led by the nose by Mr. Waoe. For, 
by none of the Colonial Governments — notwith- 
standing the temptation to make revenue out of 
their minerals — has there been so impracticable a 
proposal made as that just formulated by the Oeylon 
Government. The highest levy is a 2} per cent 
royalty at the pit's mouth in the case of well- 
established mines in Victoria. Most of the other 
Australian Governments as well we believe, as the 
Government of India, are agreed in accepting a mode- 
rate annual license and a leasing rent at so much per 
acre of land taken up. " To this complexion," most 
certainly must the terms under the proposed or- 
dinance in Ceylon come. — Our attention is called 
to a curious fact by a correspondent: that "the 
Attorney-General seems to have overlooked the 
existence of the Ordinance 7 of 1882, which dis- 
tinctly provides for licenses (with a rupee stamp) 
for lands that have been sold by the Crown and 
this I take to be the law of the land at the present 
moment. Mr. Grenier nowhere referred to this 
ordinance and it ia not repealed by the new pro- 
posed ordinance." 
