the Theory of Hail. 171 



the French gr es il) , and does not accompany a thunderstorm, he 

 classes with the hail, properly so called, that often does do so. 

 He regards both kinds as electrical phenomena, only the elec- 

 tricity has more tension in the one case than in the other. But 

 when a man is on a wrong tack, he is sure to meet with facts 

 that contradict his hypothesis. In such cases Kamtz's aphorism 

 will apply to many an observer : — " Man glaubt dennoch was 

 man gern wunscht ; " but it does not apply to Kamtz himself, 

 for he honestly states facts that are against him, and waits for 

 further light. Thus he has occasionally noticed larger hail- 

 stones in winter than in summer, although there is more moisture 

 in the air in the latter season than in the former. Smaller hail 

 is found on the top of the mountain than in the valley below, 

 just as if the increase in volume took place during the fall. 

 The inhabitants of mountain districts speak of Graupel, whilst 

 those in the valley refer to it as Hagel, 



The advocates of the electric theory of hail had no better 

 method of accounting for the large masses that fell, consisting 

 often of a number of coatings round a nucleus, than by sup. 

 posing that a small stone gathered to itself clear and opaque 

 coatings of ice during its descent. This idea prevailed long 

 after Volta attempted to explain the formation by a well- 

 known electrical process. Mrs. Somerville 8 adopts this view; 

 and Prout 9 supposes that there must be formed an icy nucleus 

 far below the freezing-point, acquiring magnitude as it 

 descends by condensing on its surface the vapour of the 

 lower regions of the atmosphere. 



As the formation of hail was firmly believed to be an effect 

 of the sudden disturbance of the electrical equilibrium of the 

 clouds, it was supposed that if the electric fluid could be 

 quietly and gradually drawn away hail would be altogether 

 prevented. Accordingly, soon alter the introduction of the 

 lightning-conductor (paratonnerre), it was proposed in France, 

 where hail is regarded as a real scourge, to introduce a hail- 

 conductor (paragrele) 10 . For this purpose, tall wooden poles 

 were erected, furnished at the top with a sharp copper point, 

 and connected by means of a metal wire with the ground. In 

 some cases the wire was omitted, but as wood is a bad conductor 

 it is difficult to see the use of the poles (even supposing the 

 theory that erected them to be valid). It was even contended 

 that the poles were equally efficacious with or without the 

 wires ; and this we can readily believe, seeing that a tree ought 

 to be more efficacious than the pole, in consequence of its 

 greater elevation and the multitude of points presented by its 



9 Physical Geography. 9 Bridgewater Treatise. 



10 Journal de Physique, 1776. 



