. 
200 Canals. ~ 
sereaieny erected by General Brisbane at Paramatia in 
New South Wales, during the mouth of June 1822. The 
elliptic elements of this comet have been calculated by M. 
Enke. It offers this important advantage, that it may be 
observed ten times in 33 years. The ellipse which it de- 
scribes is comprised in the interior of uur solar sytem. Its 
least distance from the sun is about three times jess than 
that of the earth, and its greatest distance is about i2 times _ 
greater than ils least distance. 
This comet is probably destined to furnish us with new 
knowledge relative to the mnsvlee nature of these bodies 
which have so little mass, and seem to cousist only of con- 
densed vapours. They cause no "shat perturbation in 
‘our planetary system, but they undergo themselves very 
considerable disturbances. Their courses cannot be fixed, 
if their masses gradually change, or are divided, or dissipated. 
As long however as the mass subsists, these bodies are sub- 
ject to the known laws of gravity, so that there are none of 
them, the observance of which do not afford a new proof of 
the truth of the principles of modern astrouomy.—Jdem. 
Al. Natural History—We are indebted to Mr. Bradley 
for a curious observation. He discovered that two ames 
carried into their nest forty caterpillars perhour, The bir 
appeared to him to reside in their nest ouly twelve hours in 
the day. This would produce a daily consumption of 480 
caterpillars, which in one week amounts to 3360, by a single 
pair of swallows.—Rev, Ency. Mai 1823. 
42. Canals.—Great-Britain enumerates 103 canals, of ~ 
which 97 belong to England, 5 to Scotland, and: one to Ire- 
Jand. In this number none are included which are not more 
than 6 miles long. The total extent of these eanals is 26823 
miles, of which 2471 are in England, 1493 in Scotland, and 
694 in Ireland. Thirty millions sterling is the valuation of 
the cost. The stock of some of these rose in a few years to 
15 or 20 times its original value. These various canals pre- 
sent 48 subterranean passages. 40 of which have an extent 0 
about 32 English miles. None of these works, important 9% 
they were projected prior to 1755 The patriotic and 
enlightened zeal of the Duke of Bridgewater, and the talents 
of Brindley, gave the first decisive impulse to their improve 
ments in 1759. ‘There is now scarely a point of importance 
in England, that has not a water communication with every 
ether.—Idem, 
