Miscellanies.. 165 
awild state, he observes, some birds of the same species have a 
much greater variety of notes than others, and are much better song- 
sters. : P 
Another correspondent maintains that the well known habits of the 
cuckoo, prove that the songs of birds are innate, and not acquired. 
He saw one of these birds, (which had been found half fledged in 
4 field,) in a house, in a narrow street, where it had probably never 
seen or heard one of its own species, but which at the sight of its 
Protectress, or when hungry, would ery cuckoo! cuckoo! in the nat- 
ural tone. 
Perhaps some of our readers, from their own observations or ex- 
periments, may be able to throw light on this question, which, in a 
physiological point of view, possesses some interest. 
MECHANICAL PHILOSOPHY. 
i 
1. To prevent the cracking of lamp glasses, by the sudden ex- 
pansion produced by the heat; an effectual remedy is found in run- 
ning a point of a diamond along the base of the tube. By this solu- 
tion of continuity, it is relieved from the violence produced by the 
sudden effects of the heat. A glazier can best perform the opera- 
tion with the diamond.—Jour. des Connots. Usuelles, Jan. 1830. 
A cylindrical bar of cast steel is provided, three inches long with- 
“tts handle, and about one third of an inch in diameter. It is ren- 
Blass Paper, applied longitudinally ; and itis then made perfectly hard. 
Helore it is used it must be well cleaned, not brightly polished, and 
ts surface must be smeared over with a mixture of oil and the char- 
Coal of wheat straw, which necessarily contains much siliceous earth 
ma very finely reduced state. Charcoal of the leaves of some of the 
Matsh grasses the author thinks, may perhaps answer as well or better. 
" setting a razor, its edge (which must not have been rounded by 
* strap) is brought into contact with the surface of the bar, at a very 
acute angle, proportionate to: the strength intended to be given to the 
edge, and the razor is to be moved in a succession of small circles 
from heel to point, and back again without any more pressure than 
