Miscellanies. 1 9 1 



was ascertained, that, at the time of observation, the bells of the city 

 of St. Salvador, on the Brazilian coast, had been ringing on the oc- 

 casion of a festival ; their sound therefore favored by a gentle wind, 

 had travelled perhaps one hundred miles by smooth water, and had 

 been brought to a focus by the sail on the particular situation or deep 

 where it was listened to. It appears from this, that a machine might 

 be constructed, having the same relation to sound, that a telescope 

 has to sight. 



16. Dangerous Plant among Water- Cresses. — The procumbent 

 water parsnip, Siu7n nodijlorum, is a dangerous plant of the umbel- 

 liferous class, which grows mixed with water-cresses in springs and 

 streams. When not in flower, it so much resembles the latter, that 

 it is with difficulty distinguished except by a botanist. Water-cresses 

 are of a deeper green, and sometimes spotted with brown, and the 

 extremities of the leaves are more round, and especially the last 

 leaves, which are in pairs, larger than the others, and undulated at 

 their edges. The water parsnip, on the contrary is of a uniform 

 green ; the ends of its leaves are longer and narrower, conical at 

 the extremities, and toothed at the edges. The best method of 

 knowing them well is to examine them in July, when their flowers 

 are expanded, and when they may be thoroughly distinguished from 

 each other. — Quarterly Journal of Science. 



17. Thunder Storms in France. — The Count de Triston has made 

 observations on the direction of the thunder storms which have de- 

 vastated the department of the Lorich for the last sixteen years. 

 The follovi^ing general inferences have been made by him, respecting 

 the progress and intensity of thunder storms in plain countries inter- 

 sected by shallow valleys. Thunder storms are attracted by forests. 

 When one arrives at a forest, if it be very obliquely, it glides along 

 it ; if directly, or if the forest be narrow, it is turned from its direc- 

 tion ; if the forest is broad, the tempest may be totally arrested. 

 Whenever a forest, being in the path of a thunder storm, tends to 

 turn it aside, the velocity of the storm seems retarded, and its inten- 

 sity is augmented. A thunder cloud, which is arrested by a forest, 

 exhausts itself along it ; or if it pass over, is greatly weakened. 

 When a large river or valley is nearly parallel to the course of a 

 thunder storm, the latter follows its direction ; but the approach of a 

 wood, or the somewhat abrupt turn of the river or valley, makes it 



