332 APPENDIX. 



also an account of the remarkable fog which overspread part 

 of Europe in 1783- See vol. ii. 128. of the above work, sur 

 f Extraordinaire Brouillard dc 1783. 



C. 2. 7- A disposition in the air sometimes to form rain, 

 without the precurrence of the modifications,, may be deduced 

 from the drops of rain which sometimes fall without any 

 visible clouds, even when the sky is clear. The drops, pro- 

 bably, acquire size in falling. 



C. 2. 11. Hail It is a question, Whether hail results 

 merely from the coldness of the atmosphere in which the 

 nimbus pouring it exists, or whether some other causes may 

 not be deemed necessary ? Certainly there is a difference in 

 the general appearance of the cumuli, cumulostrati, &c. which 

 precede hailshowers, and showers which only effuse rain. 

 The Abbe Bertholon has observed, that hard hailstorms are 

 generally accompanied with thunder and lightning, and that 

 the loudest thunder generally happens when the hail has 

 been greatest. " La tonnerre gronda, sans interruption, 

 pendent la chute du fameuse grele observe par M. de Ratte a 

 Montpellier, le 30 Janvier, 1741. II en a ete de meme dans 

 une grande nombre d'autres circonstances." Elect. A/W. ii. 

 195. ch. sur la Grele ct le Gresil. In the same work, vol. ii. 

 cc. 6 and 1, the author has treated amply on the peculiarities 

 of hail and snow. 



C. 5. To ascertain that our health is influenced by atmo- 

 spheric peculiarities, is a discovery of little practical utility, 

 unless it enables us to provide an antidote against their 

 effect. The difficulty of guarding against such disorders as 

 seem to be caused by the state of the air, must appear 

 manifest to all who consider the obscurity which hangs over 

 this subject, both as to the peculiar quality of the air which 

 excites the disorders, and as to the state of constitution of 



