634 
THE TROPICAL AGRICULTURIST. [March i, 1888. 
the large quantity exported to England, where higher 
prices are offered. The current price of good bark 
is in Melbourne from £5 to £5 12s. 6d. per ton, 
making £63 ; 000 to £78,750 per annum. The numerous 
witnesses called before the board of inquiry agreed 
on one point — viz., that a less quantity of bark is 
obtained from year to year, as the wattle is disappear- 
ing. Whole districts were stated to have been already 
denuded of it, and unless steps were taken to en- 
courage the growth of wattle-trees the total extermi- 
nation of this useful native production can only be 
regarded as certain. Already the supply of tanning 
bark has become scarce in England, and we read 
that English tanners depend a good deal on Spain 
and other Continental countries for their supply of 
oak-bark. England can, therefore, always be regarded 
as a consumer of our surplus wattle-bark, and it is 
not at all likely that the market will often be so 
glutted as materially to affect the price. On this 
subject Mr. Brown furnishes the following, extract 
from a letter received by him from a gentleman 
connected with one of the largest tanneries in Eng- 
land. He says: — "The matter of supply and demand 
can be pressed into a very small compass. British 
and Continental tanners are languishing for ample 
and continuous supply, and S)uth Australia exports 
in such driblets that very many of the large firms in 
Great Britain have given over using it, falliug back 
on Valonia and other barks wore fully an 1 regularly 
supplied. I may be allowed to remark here, reliable 
leather cannot be produced by intermittent and in- 
adequate supply of bark, on which the tanner relies 
when laying down his hides; indeed, in large yanls, 
such as with 50,000 hides always in the pits, it 
becomes a very serious difficuifcy, attended with anxiety 
and loss, not to be able through want of sufficiency 
of bark of a class to work them through succesfully. 
It therefore becomes a matter of necessity that the 
exports of bark may be abundant and regular to such 
an extent that tanners may confidently rely on. To 
such low export of wattle-bark have your growers 
now arrived at, that one yard could manage to take 
fully one-fourth — say, 1,000 tons — of all the bark 
shipped from yowr ports (South Australia) to England 
in 1882, and about one-third of shipmeuts in 1883. 
I was very much gratified to notice your intention of 
planting the wattle extensively ; the demand exists 
for as much as you can grow for many years, and, with 
new and increased growth, new and enlarged outlets 
will occur. I am aware French and German tanners 
hghly approve of the wattle tor tanning yurposes." 
According to the report of the Victorian Wattle 
Commission, wattles grow on almost any soil, even 
the poorest ; but their growth is most rapid on 
loose sandy pitches, or where the surface has been 
broken for agricultural purposes. When the soil is 
hard and firm, it is recommended that plough-fur- 
rows should be made at a regular distance of say 
six or eight feet apart, into which the seed are to 
be dropped. The seed should be sown in May, 
having been previously soaked in hot water, a little 
less than of boiling temperature, in which they may 
be allowed to remain for a few hours. The seed 
should be dropped at an average distance of one foot 
apart along the furrow, in which case about 
7,200 seeds would suffice for one acre of land. The 
seed should not be covered with more than about 
one quarter of an inch of soil. On loose sandy soil it 
might even be unnecessary to break up the soil 
in any way. On such open sandy soil, the furrows 
may be dispensed with, and the seed sown broadcast, 
and after the land harrowed. On this subject the 
evidence giveu by the Conservator of Forests in South 
Australia before the Vegetable Products Commission 
in December last as that of an expert is worthy of 
reproduction. Ho states: — " In establishing wattle 
plantations the seed was thrown broadcast, and a 
flock of sheep were driven over it a few times to 
trample in the seed. To facilitate propagation he 
found it better to burn the seed slightly in the 
ember's 1 of a fire rather than soak or boil it. The 
golden or black wattles wore in his opinion the most 
profitable of all forest trees. There could be no 
doubt about the superiority of the wattle over all 
other trees for fanning purposes, and it seemed to 
him an extraordinary circumstance that people should 
' hanker ' after a foreign and inferior article for no 
other reason than because the wattle was a colonial 
tree, was easily grown, and consequently undervalued." 
— Australasian . 
AGRICULTURE ON THE CONTINENT OF 
EUROPE. 
{Special Letter.) 
THE SOIL AND MINERAL MATTER — FOOD FOB PLANTS — 
LIME — CLINKERS — FODDER. 
Paris, January 28. 
Increasing the productive powers of the soil, natur- 
ally draws attention to the products themselves, and 
it is here, where the present day farmer finds science 
coming to his aid. The products he utilizes in two 
manners: directly after submitting them to modifi- 
cations, as in the case of saccharine or feculent mat- 
ters, vines, fruits &c, indirectly, as when the animal 
itself elaborates from the products the materials to 
form milk, meat, and fat. The agriculturist having 
for aim, to realize the largest amount of plant-produce, 
the question of keeping up the fertility of the soil thus 
becomes cK-sely allied to that of manures. Science 
hence, is intimately related to the conditions of the 
soil's richness ; as well as to the laws which regulate 
the formation of the tissues of animals and the composi- 
tion of plants yielding the nutrition for that tissue. 
A great difference between plants and animals con- 
sists in the sources from whence they desire their 
aliments. The plant nourishes itself exclusively on 
mineral substances; that is to say, inorganic matters 
such as water, carbonic acid and atmospheric ammonia, 
which it decomposes by means of its green organs. 
By its roots, it draws from the soil, mineral acids, 
water, and salt. With these inorganic matters, the 
plant builds its tissues and effects special combinations 
that the animal later modifies, destroys, and works up 
to form and keep in repair its own organs. 
Plants are thus the marvellous laboratory, wherein 
under the influence of heat and light are organised 
i-u\;ar, starch, gluten &c, intended by the plant as a 
reserve for the wants of its own reproduction but that 
man and animals appropriate for their food. The 
plant is thus the indispensable intermediary between 
the mineral aud the animal worlds. With water, 
carbon, and hydrogen, it forms a host of compounds 
(called immediate principles), the role of which 
science for the greater part of them ignores. How- 
ever, from a series of feeding experiments, we know 
enough about these compounds to practically guide us 
iu the matter of alimentation. Thus the organic com- 
pounds that form the mass of vegetables, aie either 
azjtized, saccharine, starchy, fatty, or woody. Theso 
azotized or nitrogenous compounds are not all identi- 
cal in various plants or even parts of a plant; as for 
example, the gluten of a wheat, the legumine of beans 
and the albumen and caseine of other plants. 
An important fact to be borne in mind is that all 
these vegetable compounds are not equally digestible, 
that is, assimilated iu the same degree by animals — 
hence, the important variations in the value of foods. 
They are all composed of carbon, oxygen, hydrogen, 
and nitrogen or azote : sulphur and phosphorus are 
never absent. Starch and sugar are found in cereals, 
the fecula of potatoes, the sugar of beet and fruits. 
The y are composed of carbon, oxygen, and hydrogen, 
but no nitrogen ; the second and third in exactly the 
same proportions as they form water. The starch 
and sugar can minerally transform themselves, and, 
circulating in the plant, accumulate in certain organs 
for reproduction iu the grain as in case of cereals j 
in beet, in the root ; in the potato, in the tuber. 
The fatty matters, like sugar and starch, are composed 
of oxygen, hydrogen, and carbon, save, that here the 
first two elements are not united in same proportions 
as in the water. The hydrogen is united to carbon in 
a greater degree, hence, their industrial importance 
for illuminating and heating ends. In certain seeds 
they can replace completely starch and sugar while 
