142 



Protection from Lightning. 



Vol. XI. 



these peculiarities are the result of cultiva- 

 tion and habit, rather than of original con- 

 stitution, if the term may be so applied. 



After the early and trying part of the sea- 

 son is past, the crops of turnips, swedes, 

 mangel-wurzel, and various tribes of cab- 

 bage, under industrious and good cultiva- 

 tion, will furnish an abundant supply of 

 food ; in respect to some of them, first in 

 their leaves, and next in their bulbs and 

 roots. Rape is likewise cultivated very ex- 

 tensively, especially in Lincolnshire, for the 

 folding and feeding of sheep. As far as my 

 observation extended, it is not usually cut 

 for sheep; but a temporary fence is put up 

 round a portion of the field, and they are 

 turned in upon it. This being eaten, an- 

 other enclosure is made; and in this way 

 they successively enter upon the different 

 portions of the field. 



That a variety of food is conducive to the 

 health of tlie animals, and to the increase of 

 the milk of the cows, seems well established 

 by general opinion and by actual experiment. 

 Dried food is much less conducive to milk 

 and to fatness than green ; and the effect of 

 dry straw is to produce almost immediately 

 a great diminution of milk. Hay is condu- 

 cive to health, and to milk, in proportion to 

 the succulent state in which it has been 

 cured, provided, however, it has attained 

 some substantial growth before being cut. — 

 ■ Colmaii's Tour, No. 7. 



A simple Method of Protecting from 

 Liightning, Buildiugs with Metallic 

 Roofs. 



By Prof. Henry, from Proceedings of American Phi). 

 Poc, June 20th, 1845. 



On the principle of electrical induction, 

 houses thus covered are evidently more lia- 

 ble to be struck than those furnished either 

 with shingle or tile. Fortunately, however, 

 they admit of very simple means of perfect 

 protection. It is evident, from well estab- 

 lished principles of electrical action, that if 

 the outside of a house were encased entirely 

 in a coating of metal, the most violent dis- 

 charge which might fall upon it from the 

 clouds, would pass silently to the earth with- 

 out damaging the house or endangering the 

 inmates. It is also evident, that if the house 

 be merely covered with a roof of metal, with- 

 out projecting chimneys, and this roof were 

 put in metallic connection with the ground, 

 the building would be perfectly protected. 

 To make a protection, therefore, of this kind, 

 the professor advises that the metallic roof 

 be placed in connection with the ground by 

 means of the tin or copper gutters which 



serve to lead the water from the roof to the 

 earth. For this purpose, it is sufficient to 

 solder to the lower end of the gutter a rib- 

 and of sheet copper two or three inches 

 wide, surrounding it with charcoal, and con- 

 tinuing it out from the house until it termi- 

 nates in moist ground. The upper ends of 

 these gutters are genei'ally soldered to the 

 roof; but if they are not in metallic connec- 

 tion, the two should be joined by a slip of 

 sheet copper. The only part of the house 

 unprotected by this arrangement will be the 

 chimneys; and in order to secure these, it 

 will only be necessary to erect a short rod 

 against the chimney, soldered at its lower 

 end to the metal of the roof, and extending 

 fifteen or twenty inches above the top of the 

 flue. 



Considerable discussion in late years has 

 taken place in reference to the transmission 

 of electricity along a conductor; whether it 

 passes through the whole capacity of the 

 rod or is principally confined to the surface. 

 From a series of experiments presented to 

 the American Philosophical Society, by Prof. 

 Henry, on this subject, it appears that the 

 electrical discharge passes, or tends to pass, 

 principally at the surface; and as an ordi- 

 nary sized house is commonly furnished with 

 two to four perpendicular gutters — generally 

 two in front and two in the rear — the sur- 

 face of these will be sufficient to conduct, 

 silently the most violent discharge which 

 may fall from the clouds. — Sillimari's Jour- 

 nal. 



A Word to Boys. — The "Learned Black- 

 smith" says. Boys, did you ever think that 

 this great world, with all its wealth and 

 woe, with all its mines and mountains, 

 oceans, seas, and rivers, with all its ship- 

 ping, its steamboats, railroads, and magnetic 

 telegraphs; with all its millions of darkly 

 groping men, and all the science and pro- 

 gress of ages, will soon be given over to the 

 hands of the boys of the present agel boys 

 like you, assembled in school rooms, or play- 

 ing without them, on both sides of the At- 

 lanticl Believe it, and look abroad upon 

 your inheritance and get ready to enter 

 upon its possession. The Kings, Presidents, 

 Governors, Statesmen, Philosophers, Minis- 

 ters, Teachers, Men, of the future, are all 

 Boys, whose feet, like yours, cannot reach 

 the floor, when seated on the benches upon 

 which they are learning to master the mono- 

 syllables of their respective languages. 



Old Jethro Tull said, that if a man was 

 too lazy to do anything else on his field, at 

 least he ought to take a stick and keep stir- 

 rinsr the soil ! 



