Scientific InteUigence. — Meteorology. 389 



5. Latitude of Calton Hill. — As the Calton Hill is one of 

 our most interesting meteorological and geological points, we are 

 happy in having an opportunity of giving the precise position 

 of the Observatory placed upon it. The Latitude of this Ob- 

 servatory, as determined by Mr Henderson, from the data of 

 the Trigonometrical Survey, is 55° 5T \^" 5 N. 



6. Mysterious Sounds. — The wide spread sail of a ship, ren- 

 dered concave by a gentle breeze, is a good collector of sound. 

 " It happened," says Dr Arnott, " once on board a ship sail- 

 ing along the coast of Brazil, far out of sight of land, that the 

 persons walking on deck, when passing a particular spot, al- 

 ways heard very distinctly the sound of bells, varying as in 

 human rejoicings. All on board came to listen, and were con- 

 vinced ; but the phenomenon was most mysterious. Months 

 afterwards, it 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 occasion of a festival ; their sound, there- 

 fore, favoured by a gentle wind, had travelled perhaps 100 

 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. 



7. Effects of Electricity on Rocks. — Electricity, as a chemi- 

 cal agent, may be considered, not only as directly producing an 

 infinite variety of changes, but also as influencing almost all 

 which take place. There are not two substances on the sur- 

 face of the globe, that are not in different electrical relations to 

 each other ; and chemical attraction itself seems to be a pecu- 

 liar form of the exhibition of electric attraction ; and, where- 

 ever the atmosphere, or water, or any part of the surface of the 

 earth, gains accumulated electricity of a different kind from the 

 contiguous surfaces, the tendency of this electricity is to pro- 

 duce new arrangements of the parts of these surfaces. Thus, a 

 positively electrified cloud, acting even at a great distance on a 

 moistened stone, tends to attract its oxygenous, or acidiform, or 

 acid ingredients, and a negatively electrified cloud, has the 

 same effect upon its earthy, alkaline, or metalUc matter ; and the 

 silent and slow operation of electricity is much more important 



