f 
668 
Supplement to ths " Tropical Agriculturist." 
MiLRCU 1. 1899. 
to drip, the funnels and contents were weighed. 
The rssult showed that the ignited soil had taken 
up 64-75 per cent of ils weight in water, theliuii- 
jgiiited soil having iti the same time aiul under the 
same conilitioiis, absorbed 57 percent of its weight 
in water. 
To check these results, the volume of water was 
measured which liad drained out of the soils, and 
from this volume the amount was calculated which 
had been retained by the soils. 
It was found that 27 per ceut of the water had 
been retained by the unignited soil, whereas -Jy 
per cent had been retained by the soil coniainiiig 
humua. This shows that in the case of the parti- 
cular soil cho.<^en, its capacity for absorbing water 
is lower when the organic matter is destroyed than 
■when the latter is present. 
In order to test the relative power of these two 
soils for retaining water, the weighings were con- 
tinued at daily intervals for a few days, with the 
follow ing results : — 
The percentages of water retained by the soils 
at the different times of weighing are shown below. 
The figures in brackets show the loss of water 
since the previous weighing: — 
Soil previously Unignited 
soil. 
67 0 
48-4 (60J 
43 6(4-8) 
39 0 (4-6) 
30-8 (8-2) (2 days) 
27 0 (3-8) 
23 0 (3 1) 
21-1 (2 3) 
19-4 (1-7) 
In the above case, although the original soil was 
not exceptionally rich in humus, and po.^sessed 
only an average capacity for water, yet it was 
suificient to show distinctly that tliis capacity for 
■water was initially higlier in the soil containing 
humus than when the organic matter had been 
removed, and also that the unignited soil parted 
■with its moisture far le.s rapidly, retaining at 
the end of ten days nearly twice as much moisture 
as did the ignited soil. 
The presence of humus in the soil is thus of 
special importance iu reference to the problem we 
are discussing, namely, tlie best way to retain 
moisture in tlie soil. Other things being equal, 
the soil, which is licn (within limits) in humus, 
■will be belter able to -with.-taud the effects of a 
dry spell than the one in ■which this substance is 
lacking. 
For the most part this ingreJient is deficient in 
our soils, more particularly in those that have been 
under cultivation for any length of time. 
The best method of applying humus is undoubt- 
edly by green manuring. What is the best ciop 
for the purpose 1 am not prepared to say. The 
crop usually recommended is cow-pea, and it un- 
doubtedly fulfils all the requirements of a green 
manure, but it is quite possible that experiment 
will indicate one more suitable to our conditions. 
Green manuring is of benefit to the soil iu other 
ways, particularly in promoting bacterial activity 
end increasing the production of nitrates. 
ignited. 
Saturated 
..o4-7 
After 1 day . 
..61-4 (3-3) 
2 „ . 
..45-3 (6'1) 
» 3 „ . 
.,40 0(5-3) 
..34-9i.5-l) 
)i 4 » • 
)> 6 " 
..26-5 (8-4) (2 days) 
» » 
..21-7 (4 8) 
)» 8 » 
.. 17-4 (4-3) 
» 9 » 
.. 13-7 (3-7) 
„ 10 „ 
..10 9 (2'8) 
But of even greater importance iii preientiug 
surface evaporation and in increasing the area 
from wliicii the plant can draw its moisture are 
the mechanical operations of subsoiling and culti- 
vating. 
in all cases where the subsoil plough has been 
used, the benefits to the crop in the increased 
power of resisting drought have been striking. 
Subsoiling enables the roots to penetrate more 
deeply into the soil in ssarch of moisture, and in- 
creases the urea from which the plant can draw 
its water. In soils th:it are not cultivated, or only 
cultivated to the depth of a few inches, there is 
frequently a hard compact stratum within u short 
distance of the surface (cfleu formed by the plough 
itsell), which resists the downward growth of the 
roots, the plant depending entirely lor ils moisture 
on the shallow upper layer of surface soil. By 
sulisoiling, by green manuring, and more particu- 
larly by maintaining a surface mulcli of loo^e soil 
during the period of the active grow th of the crop, 
we shall be able to make the most ol the water 
already present in the soil, and of all that falls in 
rain. 
In addition we have the power of choosing such 
crops or such varieties ae are found to be most 
drought-resistant. Speakingparlicularly of wheat, 
there are one or two varieties that have shown 
themselves to be less affected by the last two or 
three dry seasons than any others These varieties 
are, unfortunately, not so desirable in other res- 
pects, and the problem is still to be solved- 
The whole question that 1 have opened up is one 
that can only be satisfactorily settled by careful 
experimenting. 1 have endeavoured to place the 
more striking features of the position before us, 
and to show that the problem ol successfully resist- 
ing a drought is not so impossible of solution as 
one may imagine, and that if systematic and in- 
telligent inquiry is directed to ihe matter there is 
every reason to hope that in a few years' lime we 
shall not be so entirely at the mercy of droughty 
seasons as we now are. 
DENTITION OF CATTLE. 
TELLINO THE AGE BY THE TEETH. 
It has been stated that no accurate opinion of 
the nge of a calf can be formed until it is six 
months old; at that time the fourth molars (the 
back teeth which are used for grinding) are well 
developed. Between six and twelve months there 
are no important dental changes; the incisor 
(front or cutting teeth) become worn, and more 
space is left between them, but it is not possible 
to assert from the state of the incisor teeth 
whether an animal is under or over the age of 
one year. At one year a bullock has eight iucisois, 
and shortly afterwards the fifth molar appears. 
At the age of twenty or twenty-one months the 
two central incisors become loose, and their 
successors, the first tw o broad teeth, may begin to 
show themselves. 
At one year and seven months, in very forward 
animals, the first pair of permanent or broad 
incisors are cut, but they are never level with the 
other incisors before one year and ten mouths, and 
their perfect development is indicative of the age 
of two years, at which time the sixth and last 
