Sunrise- Shadows of Adam's Peak in Ceylon. 29 



if R/, L/ are the effective resistance and inductance, to be 

 used in Gr x , making 



G.-1 + ^ | K 1 -L 1 «+ z7TE?n , j 



Variation of L x alone makes G x a minimum when 



T S t n R /qctx 



LlM= K 1 ' + S 1 V + 2P ; - ' ' * (3o6) 



and if we take Kj = (condenser non-leaky, and not shunted), 

 we have the value of Gi given by (30 b) again, independent of 

 the condenser. Similarly we can come round to the same 

 Gr l = 2 again. These relations are singular enough, but it is 

 difficult to give them more than a very limited practical appli- 

 cation to the question of making the magnetic force of the 

 coil a maximum, although the (30 b) relation is not subject 

 to any indefiniteness. 



[In Part III. Equation (103), c/> represents or reduces to a 

 negative resistance. In Part IV., for greater convenience, <f> 

 is always a positive resistance. 



Errata, p. 350. Equation (135), put the — sign before the 

 2. Equation (137), for E read M.] 



III. The peculiar Sunrise- Shadows of Adam's Peak in Ceylon* 

 By the Hon. Ralph Abercromby, F.R.Met. Soc* 



THERE are certain peculiarities about the shadows of 

 Adam's Peak which have long attracted the attention of 

 travellers: a good deal has been written about them, and several 

 theories have been proposed to explain the observed pheno- 

 mena. In the course of a meteorological tour round the 

 world, the author stopped in Ceylon for the express purpose 

 of visiting the Peak, and was fortunate enough to see the 

 shadow under circumstances which could leave no doubt as to 

 the true explanation, and which also entirely disproved certain 

 theories which have been propounded on the subject. 



The following account is taken from a paper by the Rev. 

 R. Abbay, many years resident in the island, entitled " Re- 

 markable Atmospheric Phenomena in Ceylon," which was 



* Communicated by the Physical Society : read November 13 ; 1886. 



