200 Canals. 



servatory, erected by General Brisbane at Paramatta in 

 New South Wales, during the month 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 less than 

 that of the earth, and its greatest distance is about 12 times 

 greater than its least distance. 



This comet is probably destined to furnish us with new 

 knowledge relative to the singular nature of these bodies 

 which have so little mass, and seem to consist only ot con- 

 densed vapours. They cause no sensible 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 oftlie principles of modern astronomy — Idem. 



41. Natural History. — We are indebted to Mr. Bradley 

 for a curious observation. He discovered that two sparrows 

 carried into their nest forty caterpillars per hour. The birds 

 appeared to him to reside in their nest only twelve hours in 

 the day. This would produce a daily cons-umption of 480 

 caterpillars, which in one week amounts to 3360, by a single 

 ..pair of swallows. — Rev. Eiicy. Mai 1823. 



42. Canals. — Great-Britain enumerates 103 canals, of 

 which 07 belong to England, 5 to Scotland, and one to Ire- 

 land. In this number none are included which are not more 

 than 5 miles long. The total extent of these canals is 20821 

 miles, of which 2471 are in England, 149| in Scotland, and 

 ^9^ 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 of 

 about 32 English miles. None of these works, important as 

 they are, 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 

 sther. — Idem. 



