JULY I, 1891.] THE TROPIOAt. AOI«tJt3LTUR1ST. 
practically sterilised when it contaias only from 1 to 
3 per cent, of coffee extract. One is glad to hear coffee 
80 well spoken of, and bushmen and travellers in 
Australia ought to take it instead of tea, inasmuch as 
coffee requires cooking (ought to be boiled and produced 
as a decoction), buS this process reaUy converts tea 
into a dangerous fluid, for tea should never be drunk 
except as an infusion. 
Some valuable botanical experiments in the life-history 
of green leaves have recently been published by Professor 
Scbimper. They relate to practical experiments made 
by himself on the pirt played by mineral salts in 
the econoii)y of plants. He shows that, immediately 
on germination, the pho?phate3 begin to leave the seed?. 
In conjunctioa with organic substaucPS, their ultimate 
goal is the growing poiut and the mesophyll (or middle 
substance of leaves). The miutral acids, he shows, 
pass through tha inter-cellular parts of stems and leaf 
through whicb the sugars and amides alto pass. 
Potassium passes upwards out of the .seeds as potassium 
pbospbate. The leiives ot 1 he vine pUnt more particu- 
larly (and this ought tointerest Australian viticulturists) 
contain, in addition to oxalate o( lime considerable 
quantities of tartrate and malate of calcium (or lime). 
Lime has practically (by a student of oraganic chemis- 
try) to be regarded as a carrier of otber and perhaps 
more important and fragile chemical particles to the 
parts of the growing organism where they are required, 
and where, as in a market-placi?, they are immediately 
picked up. Then the "cirrior" (?tnie) returns to the 
earth as it was, bs it does in the case of old bones 
which dead men and animals cannot walk about with. 
One importait botanical fact has recently been 
proved — that plants can be steril sed. This ij effected 
by parasitic fuugi attacking pistils and stamens res- 
peolively, and, of course, destroying them. There is 
a tendency among botanists ta believe this may have 
been the inducing cause of the c rganisatiou of monoeciotis 
and dtcecoius plants, which are not confioed to any 
particular botanicil order, although they are more 
abundant in some than others. Monoecious (one honse- 
liold) signifies that pistils and stamens are found of 
the same plant, and dicecious (two households) on 
separate plai ts. 
A French wine merchant, M. Girard, hag for some 
time pest been undertaking practical experimenta to 
prove the possibility of profit»bly gri.'Wiug potatoes for 
the manufacture of [potato brandy. He declies it 
is an industry which cannot fail to be commercially 
successful. Only ought not the words " potato brandy" 
to be on the label of each bottle ? — Australasian. 
BURNT EARTH. 
As the subject of burnt earth is commanding a good 
deal of attention from gardeners at the present time, 
and we think properly so, a few words upon the 
scientific side of the question may not be out of 
place. 
The improvement of sterile soils by burning is a 
very old practice, and was known to the Romans. 
The theory of its operations has occasioned much 
discussion, both among scientific men, horticulturists, 
and farmers. 
It is quite evident, however, that the action of 
burning a soil is not a merely mechanical one of 
opening the texture, but is decidedly chemical. 
The Durning process does not answer on all clay 
soils, but it does answer on most of them, especially 
on the Oxford clay, which crosses England in a 
wide band ; it answers also in Essex, Cambridge- 
shire, Bedfordshire, and in Worcestershire. 
The operation renders the soil less compact, less 
tenacious, and retentive of moisture ; and when 
properly performed, it converts a substance that was 
stiff, damp, consequently cold, into one powdery, dry, 
and warm, and much more suitable as a bed for 
vegetable life. A plant to grow up strongly and freely, 
must have not only good and abundant food, but a 
suitable and healthy abode ; it must be well fed anid 
well bedded. 
The great objection usually made to burning soils 
is, that it destroys vegetable and animal matter, or the 
manure in the soil ; but in cases in which the tex- 
ture of its earthy ingredients is permanently improv- 
ed, there is more than a compensation for the tem- 
porary diaadvautage. !( must always underistood 
tiat the ashes of burnt earth are best when they- 
are blackest — that is, when produced by slow combus 
tion. 
The burnt substance, when mixed with other soil, 
makes it work more easily, renders it more friable 
and less tenacious, and tends to make strong, thin, 
sterile clay-soils less compact, and more productive. 
The vegetable matter which v,'as burnt is quickly 
converted into an enriching ingredient, which in some 
classes of soil may lie dormant for ages. Whenever 
there is an excess of inert vegetable matter, the 
destruction of it by fire is most beneficial ; the ashes 
being mixed with the soil produce vigorous and healthy 
Elants on ground which before was unproductive ; 
urning, therefore, destroys the inert vegetable matter 
of a soil, and converts it into a valuable manure. 
In well and satisfactorily burnt earth, it is esti- 
mated that about one-sixth of its weight should be 
destroyed, the other five-sixths being brought into 
more vigorous action, and resulting in positive good. 
On the other hand, coarse sands, or rich garden soil, 
whose texture is already sufficiently loose, and the 
organic nitrogen sufficiently soluble, the process of 
burning must be'detrimental. — J.J.Willis, Harpenden. 
— Gardeners' Chronicle. 

Salt in Agbicultubb. — A further communi- 
cation from "B." in regard to the use of salt in 
agriculture has been sent us for publication. He 
gives us some curious information about the use of 
salt for cattle and the effect it has upon the pro- 
duction of milk, and mentions the custom of placing 
a block of rock salt in the stable for cattle to lick. 
This was — and probably is still — a common thing 
upcountry in cattle-sheds, and perhaps "B." may not 
be aware of the manufacture of cylinders of salt on 
a metal sprindle which can be hung up in convenient 
positions in the sheds or out of doors. As re- 
gards the working of the ground in the Mahaoya 
valley, has "B." ever tried thatching the ground with 
mana grass or other vegetable litter'/" We have seen 
wonderful results from this operation in a dry district 
upcountry ; whilst the rest of the estate was absolutely 
burnt up and drooping and the surface as hard as a, 
brick, the soil beneath three or four inches of thatch 
was always moist and friable. The grass itself was 
fired into tinder and thence rose the danger of fire 
which was only avoided by a liberal sprinkling of 
earth ever the thatch. If "B." will point out to 
Mr. Dawson how he proposes rendering the salt 
unfit for human food, it is very probable he would 
be allowed to make a trial. — Local "Times." 
The Tallow Tbee in China —Mr. Hosie, tlie 
British Consul at Wenchow, in his last report describes 
a curious vegetable product which is cultivated in 
his district. This is the tallow tree (Stillingia 
sebifera, Roxb.), the fruit of which produces oil as 
well as tallow. The berries, which resemble coffee- 
beans in appearance and size, are first steamed and 
then pounded in an ordinary rice-trough. By pounding 
the soft mealy mesocarp is partially separated from 
the kernels. The whole is then placed in a bamboo 
sieve, the meshes of which are just large enough 
to allow the mealy matter to be scrubbed through 
and small enough to keep back the kernels, which 
are hard, black, and about the size of peas.' From 
the mealy matter the tallow is expressed iu primi- 
tive wooden presses. To obtain oil the kernels 
are dried and passed between two millstones held 
at such a distance apart by means of a bamboo 
pivot as to crush the hard shells of the kernels 
without injuring the white interiors. The whole is 
then passed through a winnower, which seperates the 
broken shells from the solid matter. The latter is 
then placed in a deep iron pan and roasted until it 
begins to assume a brownish colour, the process being 
accompanied by continual stirring to prevent burning 
The crushed shells make an excellent fuel for the 
purpose. It is then ground by a huge stone roller 
in a circular stone well, steamed, made into circular 
cakes with bamboo and straw casings, and passed 
through the wooden press. A good lighting oil of 
a brownish-yellow colour is thus obtained. The 
allow is called " p'i yu "—that is, skin, or external, 
oil.— Loiidou Tunes, 
