-MaUch 1, 1899.] 
Supplement to the '^Tropical Agriculturist." 
10 cubic centimetres of bile into the dewlap. They 
had not had rinderpest. 
Augustus. — All eating and looking well. Swell- 
ing coratnencing at the seat of inoculation. 
August 26. — All well. All four had a fairly hard 
swelling, the bize of a man's fist, at the seat of ino- 
culation. 
August 28. — All well. Swelling decreasing. 
August 30. — All well. Hardly any swellingut all. 
September ^. — The ten days in which protection 
is said to be given having elapsed, the four bulls 
•were tied in the infected sheds along with animals 
suffering from rinderpest, in order to see if they 
contracted the disease. 
September 70.— The four bulls having been ex- 
posed to infection for a week were washed with a 
disinfectant solution and sent back to work the 
following Monday, 12th. None of them were ill 
in the slightest degree. 
II. 
August ^8.— Two bulls died, and on postmor- 
tem examination I found the bile good in one case 
nnd unfit for use in the other. In the former the 
bull had suffered badly and died after three days. 
I inoculated six healthy bulls and a calf. 
August 30. — All eating and looking well. A 
large swelling at the seat of inoculation, the size 
of a football. 
September 6. — All well. The swelling at the 
chest has been gradually decrea.^ing for some days. 
All the six were sent back to work again. 
October 6. — After a month none have been ill ia 
any way. None of them had sores or abscess at 
the chest, or suffered in the slightest degree from 
the inoculation. 
Experiments will be continued when the oppor- 
tunity arises. The method is very simple and 
quite harmless, if properly carried out. 
G. W. STUEGESS, 
Government Veterinary Surgeon 

SOIL MOISTUEE. 
(Concluded.) 
Evaporation, both from the leaves and from the 
surface of the ground is, under normal conditions, 
continually going on, as we have just seen, to an 
enormous extent. 
It is at its greatest when the air is dry, the 
thermometer high, and the wiiul strong. These 
are, of course, the conditions that prevail during 
the greater part of a dry spell ; and the evil effects 
of a drought are due, not only to the actual want 
of rain, but also to the prevalence of conditions 
which help to diminish the store of water already 
in the soil. It is true that we cannot regulate the 
temperature nor control the wind, but something 
could be done in the way of cooling and moist- 
ening the air and breaking its force by the judicious 
planting of trees, or the less ruthless destruction 
of the existing limber. 
A belt of trees, even at some distance from the 
wheat-paddock, exerts quite an appreciable influ- 
ence upon the crop. 
With regard to the surface evaporalion, tlie con- 
ditions are somewhat more under control. The 
same external conditions influence the evaporati n 
from the surface of the soil as from ihe ciop ; that 
is, other things being equal, the loss by evaporation 
is greatest during hot, dry, windy days, but in this 
instance we have an ally in the retentive power 
for moisture of the soil itself, and there are several 
ways of checking undue evaporation from the sur- 
face. 
The minimum of surface evaporation will be 
found in a well-drair.ed soil, fuirly rich in humus, 
cultivated to the depth of about 6 or 7 inches, and 
with a light surface mulch about one to t wo inches 
deep. This mulch may be obtained in i)ractice by 
lightly hoeing or harrowing the surface at intervals. 
The benefit of hoeing in conserving moisture is due 
to the fiict that in its natural condition a soil in 
good tilth resembles a sponge, the water from 
below finding its wi;y upwards along the minute 
channels formed between the particles of soil and 
evaporating when it reaches the surface. The 
action of hoeing is to disturb this state of things, 
nnd to break up these channels for a time at least, 
and so to prevent too rapid evaporation until the 
water has found new channels. 
In a true mulch, such as litter, or straw, or leaves, 
&c., this capillary action is maintained throughout 
the soil, up to the surface ot the soil proper and the 
further upward movement is checked by the mulch. 
In hoeing or harrowing, the surface of the soil 
itself is converted, temporarily, into a mulch, and 
the effect is the same. Such a layer of 1 to 2 
inches of liglitly harrowed surface- soil has all 
the advantages of a mulch of straw or leaves 
and none of the disadvantages. This surfnce 
mulch of loose soil must be maintained during 
the growth of the crop by repeated harrowing, 
the object being to keep a Liyer of loose soil 
on the surface and not allowing it to compact. 
In order to be able to hoe, the seed must 
be drilled in rows, a practice which has not 
yet received the attention it deserves iu this 
Colony. 
Humus, or decaying organic matter, as well 
as being of distinct value as a fertiliser is of 
still greater value in modifjing the texture of 
the soil. The importance of humus has already 
bepit dealt with at greater length in the Farmers' 
and Fruityroivers' Guide, we are only concerned 
in this plice with its relation to moisture. 
Probably a description of the following experi- 
ment, the details of which were carried out 
by Mr. Barker in the Departmental laboratory, 
will best serve to show the extent to which 
the presence of humus affects the water-holding 
power of the soil. 
The experiment had for its object to ascertain 
whether or not the capacity for water of a soil and 
its retentive power for water were diminished 
when the humus was destroyed. 
The experiment was made on a soil containing 
18 per cent humus. A portion was taken, and 
ignited at as low a temperature as possible, until 
the organic matter was entirely burnt off. It was 
then allowed to remain exposed to the air for 
about a week before being weighed, in order that 
it might be, as far as possible, under exactly the 
same condiii.)n.s as i:omoi>ture as the origimil soil. 
Equal weights were then taken of the igniiod and 
unignited soils, and placed in large funnels, the 
Weigh' s of which weie known. The soils wero 
then drenched with the siime qiumtity of water, 
iu the manner iu which the capacity for water is 
usually taken, As soou as the water had ceased 
