422 Mr. W. R. Bitt on the Hail Storm of Mat/ 5, 1850. 



STREAMS DOWN ALONG WITH THE RAIN AND THROUGH 



it; a7id the shmsoer is propagated in all directiojis till the 

 whole mass of cloud is brought into action" The great body 

 of cloud, as appears from observations at the commence- 

 ment and close of the storm, was moving from the S.W., 

 from which the legitimate inference is, that the storm itself 

 was moving from S.W. to N.E. When the black threat- 

 ening appearance was first noticed in the N.E., rain was 

 falling from the bases of the cumuli; it did not, however, ap- 

 pear to be of great extent ; and at the same time the clouds 

 in the S.W., W. and N.W., presented, especially as con- 

 trasted with those in the N.E., a remarkable /zg^/zi appearance : 

 the storm did not pass over this observatory from the S.JV. 

 Shortly after the rain commenced, and during the continuance 

 of the hail, the well-defined black masses of cumuli were ra- 

 pidly resolved into nimbi ; and it appeared to the writer that 

 this resolution of cumuli into nimbi occasio?ied the apparent 

 progression of the storm from the N.E. Unfortunately he did 

 not particularly observe the character of the clouds in the 

 S.W., W. and N.W. ; but his impression is, that during the 

 entire period of the storm the atmosphere was much lighter 

 in those directions. It would be extremely interesting to learn 

 at what point nimbification began, and how far it extended 

 on each side the nucleus. The apparent conclusion from the 

 phaenomena is, that when nimbification commenced it rapidly 

 extended in all directions from a central point. 



From information that I have received, I have some reason 

 to conclude that the area over which the hail fell was very 

 circumscribed. The hail was not noticed either at Mortlake 

 or Petersham, both near Richmond ; the clouds were moving 

 towards the former village, and the dark threatening appear- 

 ance was seen in that direction ; so that the nucleus was most 

 probably between Richmond and Mortlake, but nearest the 

 former place. The storm was observed at Ham. 



The phaenomena above detailed appear to me so illustra- 

 tive of the views embodied in my paper on the connexion of 

 Atmospheric Electricity with the Condensation of Vapour 

 (vol. XXX vi. p. 161), that I have thought they may not be 

 altogether uninteresting to the readers of the Philosophical 

 Magazine. 



Will you be kind enough to notify in your next Number 

 that I shall be happy to receive from any quarter observations 

 hiade in conformity with my instructions in the Hurricane 

 Guide ? if corrected, so much the better ; and as opportunity 

 may offer, such observations shall undergo discussion, at least 

 insofar as they may throw light on the great aerial move- 



