June i, 1882.] THE TROPICAL AGRICULTURIST. 
limd in the neighbourhood of forests received one- 
quarter more rain in the year than that which was 
denuded of trees. It would certainly be worth the 
trouble involved, if the Government As'ronomer or the 
Forest Board, or, perhaps, the Director of the Botanical 
Gardens himself, would make similar trials in this 
ouy, 
'Hi, 
to which we have already 
attention, namely, that between the rainfall on 
West-terrace anil on East-terrace is one which would 
justify further investigation, as the differences which 
we have pointed out cannot be simply a matter of 
chance, but are probably due to the influence of trees. 
The controversy on this subject is likely to be in- 
terminable unless some steps are taken to determine 
definitely whether the presence of trees in this climate 
tends to augment the rainfall. The Forest, Board has 
gone to work, most of the members firmly believing 
the affirmative, while the Surveyor-General, whose 
opinion is entitled to respect, inclines with equal resol- 
uteness to a negative answer. We have already 
stated our belief that the For jst Board, in order to 
establish its raison d'etre, does not require to prove 
the theory. The providing of a supply of timber ; 
he encouragement of profitable industries connected with 
forestry; and generally the work of rendering the 
Open plains of the colony more habitable, must 
afford ample grounds for the existence, of the Board, 
independently of the rain question. However, if the 
members, or rather the, late members, wish to estab- 
lish the theory they cannot do better thau collect 
and record the experiences of those parts of this 
colouy which have been at one time covered with 
timber, and which have since been denuded of it. 
Certain it is that such an enquiry would be justified 
by the authority of nourly all the best writers on 
meteorology and physical geography. The connection 
between forests and rainfall is not anything of a 
mysterious or incomprehensible nature. On the con- 
trary, it can be explained by very well-defined physical 
laws. One of these is the law of the radiation of 
heat. A forest-clad plain is much slower both iu 
parting with and iu receiving its heat than is a bare 
one ; and, consequently, it is much more frequently 
at a different temperature than the clouds, and must, 
therefore, assist in causing them to fall. The con- 
duction of electricity from the atmosphere is another 
way iu which it has recently been demonstrated that 
trees assist the fall of rain. A third point to be 
observed is that trees interrupt the lower and mobster 
currents of air, and facilitate the deposition of dew 
at night, and, similarly, of light rains in the winter 
time. It should be noticed that the place for ob- 
servations on this important point is not one in which 
trees have been cut down only to make room for 
houses or other erections, as in a city. The com- 
parison should bo between a plain covered with trees 
and one absolutely bare. There is no reason why 
this vexed question should not be settled in a very 
short time, if the enquiries would only proceed in a 
reasonable spirit, instead of, as at present, contenting 
themselves, the one party with a bare affirmative and the 
other with a bare negative.— South Australian Register. 
[The difference in rainfall for two periods is so 
slight as possibly to be merely the result of a different 
mode of observation. Curiously enough not a word 
is said about the inlluoneo of the neighbouring Mount 
Lofty on the rainfall of Adelaide. If that monnl dn 
were removed, tho result would bo more disastrous 
than all tho denudation of trees which lias occurred. 
Kvon if tree planting does not increase rainfall, it 
will do good otherwise.— Ed.] 
suggestions which may be adopted as a basis for com- 
puting the conipeu-ation for manures unexhausted 
at the termination of a tenancy. The following is 
the list:- 
1. Lime.— In all soils to which it would be proper 
to apply lime, and the proper quantity (over five tons) 
is applied, it is good. In light soils, for ten crops; 
iu good, deep, loamy soils, for twelve crops; in clay 
soil its beneficial effects are not lo&t in fourteen or 
fifteen crops; and in peat soils it is good for ten or 
twelve crop?. In new grazings its effects are seen in 
twenty crops, and in old permanent pastures its effects 
are discernible for thirty years. 
2. Horse, Cow, and Town Manures.— When applied 
in sufficient quantity (above fifteen tons), these manures 
are exhausted in the ordinary five-course shift. T?he 
rate is more rapid in the first two than in the re- 
maining three years— say, half in two years and the 
other haif in the remaining thre9 years of the rotation. 
3. Guanos. — If highly ammouiacal, the exhaustion of 
the nitrogenous matter will be rapid in the first aud 
second year. But there are other valuable fertilizing 
elements in good guano, and these are more enduring. 
Experience demonstrates that half the manurial value of 
guano is exhausted in the first crop, and the other half 
left available for the remaining crops of a rotation. 
Its beneficial effects are obvious in most soils, even in 
the fourth year of a rotation. 
4. Bones. — Bone-dust will benefit, according to the 
nature of the soil, from three to five crops of cereals 
and grasses. Dissolved bones are more rapid in the 
rate of exhaustion. The first crop takes about one- 
third of the manurial value ; the second will bring the 
one-third up to a half, and a third and fourth crop will 
exhaust the whole. 
5. Phosphates decomposed by vitriol will be ex- 
hausted at the rate of dissolved bones, and ground 
phosphates at that of bone dust, and the rate of exhaus- 
tion may be taken as that of guano. 
6. Sulphates are volatile, and experience leads to 
the belief that, when applied in sufficient quantities, 
these are mostly exhausted by the crop to which 
applied, to the extent of two-ttiirds, and to the ex- 
tent of the balance in the next crop, and are of 
nppr.'ci 
bsequent crops in Seot- 
> state that Mr. Lawes - s 
to be different. 
nip 
! manures. — inese are the manures pre- 
leeial crops, and known by the name of 
which they are applied, such as " tur- 
l," &c. The rate of exhaustion of thee 
on the ingredients of which they are 
Experience would class the rate higher in 
nan sulphates, but of less endurauce in 
i guanos— say three years— two-thirds Best year, and 
one-third the remaining two years. 
8. Clay. — A well-known application to peat and 
I other vegetable soils, which endures for seven years 
! at least, and which may bo held to l>o exhausted 
one-seventh of its cost each year. In Scotland the 
oost of its application is its only cost. -Indian Tea 
Gazette. 
THK UNKXHAUSI'KI) V ALUKS OK MAN I' KM. 
At the special request of Lord Koscbrry, the Scot- 
tish Chamber of Agriculture have prepared a list of 
AG RICULTURA L ITEM s. 
(From the Qutentlander, 26th March ) 
The largest room iu every cheese and butter factory 
of the land is the room for improvement. 
An American farmer reports DO appar ut injury to 
pints of an asparagus bed covered with a coating of salt 
so much as "2 in. thick. 
fiffaoh selected bind ill South Austral .1 is North of 
Govder's line of rainfall, and useless for Agriculture, 
The wheat harvest just garnered in 801 h Aus r.ihu i« 
small but bettor in quality than ha* I ecu «e*n fur 
years. 
