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Miscellanies. 361 



^shford, Conn. — Black tourmaline, abundant in the granite in 

 Eastford. Cyanite in gneiss and detached masses, the bladed crys- 

 tals sometimes a foot in length, in a part of Ashford called locally 

 Pilfersbire, on a cross road from Abington lo Eastford. 



Canterbury, Conn. — Precious garnets, more or less perfectly crys- 

 tallized, in granite. Some of them are nearly an inch in diameter, 

 and of a beautiful amethystine color. They are in loose blocks of 

 granite that have been blasted from the road, about three miles from 

 Canterbury village, on the road to Norwich. 



BrooMyn, Conn. — Epidote, crystallized and compact In gneiss; 

 chlorite, specular oxide of iron, associated with epidote in tliin veins, 

 in gneiss, common. Precious garnets, small, but very beautiful, in a 

 fine white granite, three miles from the courthouse, on the road to- 

 wards Windham. Staurotide in mica slate, about three miles from 

 the last locality, on the road towards Windham, near Howard's Inn. 



Plainjield, — Epidote, Iron pyrites in gneiss, found in considera- 

 j ble quantity, in digging the foundation of Harris' manufactory. 



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3. Mode of adjusting lightning rods. 



TO THE EDITOR, FROM MR. P. B. WILCOX. 



Columbus, (Ohio,) May 21th, IS30. 



Sir — ^The Scioto valley in which this town is situated, is liable 

 to heavy thunder storms. A contrariety of opinion and of prac- 

 tice prevails in attempting to secure houses by rods from the effects 

 of lightning ; and I have been requested by several gentlemen, to 

 address you upon the subject, to ascertain the proper manner in which 

 to put up rods, so as most effectually to protect buildings. Some of 



the difficulties are as follows : 



1. The depth to which the rod should be inserted in the ground. 

 It has been remarked in this State and in Kentucky, both limestone 

 countries, that very frequently rods furnish no protection to houses. 

 In the summer season the earth becomes perfectly dry for several feet 

 helow the surface, and it is supposed by some, that there is not suffi- 

 cient moisture at the termination of the rod in the ground. 



2. Another difficulty is, the proper height of the rod above the 



highest point of the building. 



3. Another very serious difficulty seems to be the manner in which 

 tie rod should he attached to the building .—The common practice 

 here is to place the rod by the side of the house, and at proper dis- 



VoL. XVIII.— No. 2. 46 



