171 



to be destroyed by any electrical shock to which it may be sub- 

 jected ; this system has had a trial of 18 years in the British 

 navy, and even the common sailor has merged his suspicion 

 into admiration. 



The Committee declare it to be their opinion, that any 

 system of conductors, sufficiently elevated, presenting a suffi- 

 cient number of points, perfectly continuous, presenting 

 competent surface, and pursuing the most direct route to the 

 earth, claims and should receive the full confidence of the 

 public. 



4. Are some trees better conductors than others, as the elm 

 for instance than the pine, and therefore more efficacious 

 protectors 7 



In the cases of this nature Tvhich have been noticed the past 

 year, it has almost invariably been found that the pine when 

 struck has been shivered. But the elm receives the shock 

 more patiently, perhaps its exceeding strength enables it better 

 to bear tie shock. The oak usually manifests the effects of 

 the contact. The North American Indians have a tradition, 

 which declares that the beech is never struck by lightning. 

 Tiberius, the emperor of Rome, wore a wreath of laurel as a 

 protection from lightning. Since tradition is usually founded 

 in truth, we may infer that, so far as its authority extends, the 

 affirmative is the true answer to this question. 



Possibly the trees whose branches make a small angle with 

 the trunk, are better conductors than those constructed with 

 greater angles. The angles of the branches of the beech 

 and the elm are small ; those of the oak, the apple, the locust, 

 the sycamore and the pine are large. I have spent six years in 

 the vicinity of a grove of Lombard y poplars, but knew no 

 instance of violence done to them by lightning, or to the build- 

 ings which they shaded. 



Has the maple, the willow, or the birch, been known to 

 suffer from electricity 7 



Eacts in relation to this question are few indeed, but what 

 there are, lead to the conclusion that some trees are better 

 conductors of electricity than others. 



5. Are the amount and operations of the electric fluid con- 

 siderably affected by the growing and ripening harvests ? 



It may be regarded as an established fact, that a chemical 

 change in the form of bodies is attended with the development 

 of electricity. 



