22 
MAGAZINE OF SCIENCE AND ART. 
As we do not wish to give publicity to 
the statements of inventors, who generally 
manage to exaggerate the capabilities pf 
their schemes, we enquired of the owner 
of the machine we saw at work what was 
his experience of its powers. 
We are bound to say, that he was en¬ 
thusiastic in its praise. With one horse 
working this machine, he can cut 10 or 12 
cwt. of chaff per hour, and the cutting the 
weekly supply of chaff, and cracking the 
com, for their large establishment, varying 
from 50 to 100 horses, is all done by one 
horse and two men in one day. We 
need not point out the economy of feed 
from this process, by which what would 
otherwise be rejected by the horse, is 
eagerly devoured; but we may remark, 
that Mr. Burt considers that, in three 
monthsuse, he shall save all the expenses of 
the purchase and the fitting up the machine. 
This power is equally applicable to the 
work of the farm, and it is easily trans¬ 
portable. By its means a horse can churn 
the milk, thrash the corn, cut the wood, 
draw the water, and, in fact, perform all 
those offices to which machinery can be 
applied. We recommend our agricultural 
friends, who are most interested in this in¬ 
vention, to inspect the working of this 
machine at Messrs. Burt and Co.’s, any Sa¬ 
turday morning. The cost of the machine 
is about £50. 
LIME. 
We need scarcely inform our readers that 
lime is a very scarce, and, in consequence, 
a very expensive article, in Sydney. We 
have long considered its source of supply 
one of the most important subjects for the 
investigation of the geologist. We believe 
that the price of slacked lime in this city 
varies from one shilling and sixpence, to 
three shillings a bushel. In the ab¬ 
sence of limestone, nearly all the lime that 
is used here, is obtained from the calcina¬ 
tion of shells. This does not produce lime 
of a strong, durable character, and we 
question whether it possesses any hydraulic 
qualities. 
We do not profess any practical in¬ 
formation on the matter, but we have 
noticed that much of the plaster-work in 
this city is liable to “ saltpetreing,” that 
is, the walls are often covered with an 
efflorescence of a white fleecy appearance, 
which is entirely destructive of any paint 
that may be placed on them. This is, bv 
soine chemists, attributed to the animal 
matter present in the lime forming a nitrate 
of potassas, and it would appear quite na¬ 
tural that this ingredient should be found 
more plentifully in lime derived from sea 
shells, than that from calcareous rocks. 
Some idea may be obtained of the import¬ 
ance in regard to expense of this material, 
when we state that we have been recentlv 
informed by a practical builder, who has 
just finished two small brick-built houses 
in Castlereagh-street, that the cost of the 
lime alone was between £80 and £90. 
We are aware that the labour of collecting 
shells, and bringing them to this port, em¬ 
ploys a large number of men, and several 
small coasting vessels. We believe a more 
permanent, and, in fact, an inexhaustible 
supply might be obtained from the coral 
reefs that skirt the numerous islands to the 
north. In fact, we cannot doubt but tjiat 
this would be a very profitable branch of 
industry. Instead of hundreds of men 
employed with painful toil in collecting 
the scattered and precarious store of shell, 
in the harbours of the coast, we would 
suggest that a good sized schooner be des¬ 
patched to one of the northern islands 
within a week’s sail of our harbour, and 
on the beach she might pick up heaps of 
coral rock, already lying quarried by the 
action of the waves, in vast profusion. 
We believe that this, when burnt, would 
give at least as valuable a lime as we pos, 
sess at present, and that it could be sold 
at a large reduction of cost. 
Since the above was written, we have been 
informed that a very superior quality of 
limestone has lately' been discovered in the 
vicinity of Sydney, and we have inspected 
a specimen, which appears of the very 
finest quality of carbonate of lime. We 
understand that the exact locality of this 
deposit is a secret, but we know that a 
sample is in the hands of an analytical 
chemist of this city, and that he pronounces 
it to be of remarkable purify. It has all 
the appearance of a fine white marble with 
pink veins. 
STUMPING. 
At the June meeting of the Agricultural 
and Horticultural Society the following 
paper was read, by Mr. Joseph Dyer. 
We did intend to illustrate it with an 
engraving of the most recently invented 
