38 BOARD OF AGRICULTURE. 



EVENING SESSION. 



The Evening Session was occupied by an interesting- and in- 

 structive lecture by Prof. Fernald on "Protection from Light- 

 ning-." 



Lightning and the Means of Averting its Destructive Effects. 



In a single hour, it will not be possible to consider with minute- 

 ness, and in its varied relations, the subject which is to engage us 

 to-night. However important might be an elaborate discussion of 

 the nature and effects of that subtle fluid, which as our agent may 

 speed our messages swift-winged across a continent, or as our 

 master may bring instantly terror and disaster to ourselves and 

 our households, we can only attempt on the present occasion to 

 offer a few thoughts in regard to " Lightning and the Means of 

 Averting its Destructive Effects," which we hope may not be 

 unworthy of your thoughtful attention. 



If it be desirable to rear homes for ourselves and our children, 

 it is equally desirable to protect those homes, whatever may be the 

 form in which the threatened danger may present itself. 



If it be desirable to engage in commercial pursuits, — to fit out 

 vessels and send them upon boisterous seas, it is equally desirable 

 that they go prepared, not only to buffet successfully wind and 

 wave, but to avert the shafts of the storm-cloud, which unaverted 

 might prove their destruction. 



If liability to accident and harm attend our every footstep, does 

 it not become us as rational beings to consider, whether by any 

 possibility any of the forces of nature which threaten us may be 

 rendered powerless, and be made to play harmlessly at our feet? 



Your attention is solicited to considerations upon — 



1st. The nature of lightning as indicated by its manifestations, 

 and effects. 



2nd. The extent of danger from its stroke. 

 3d. Means of protection from it. 



Meteorologists ordinarily recognize four forms of lightning, viz : 

 zigzag lightning, ball lightning, sheet lightning, and heat light- 

 ning. 



As regards the third and fourth forms we must content our- 

 selves with simply a definition. Sheet lightning is a diffuse glare 

 of light, sometimes illuminating only the edges of a cloud, and 

 sometimes pervading the entire surface of the clouds from which 



