22 



Hon. Ralph Abercromby. Relation between 



greater. The isobars are drawn at intervals of 0'4 inch, and as the 

 longer diameter is only about 315 miles, and the shorter one 

 245 miles, the intensity of the depression can be readily realised. 



But perhaps this will be even more strikingly exhibited if we look 

 at the barogram during the typhoon at Manila, as given in fig. 10. 

 There we find many of the typical features of a tropical cyclone, in 

 the strong diurnal variation of pressure on the top of the general 

 diminution of pressure which preceded the typhoon by several days r 

 and in the very sudden depression near the centre of the hurricane. 



The incurvature of the wind is very pronounced ; and it is y 

 perhaps, important to note that the strong supposed rising impulse in 

 front of the centre, to which we have already alluded, is associated 

 with a rearward compression of the isobars. 



The vortex was almost exactly centred over Manila at the moment 

 for which the chart is constructed, and though the rain ceased and 

 the overcast sky grew higher, there was no blue visible. 



The velocity of the whole typhoon appears to have been about 

 19 miles an hour. 



Hong Kong. — From Manila the author went to Hong Kong, where 

 Dr. Doberck, of the Observatory at Kow-long, has been giving much 

 attention to the subject of typhoons. 



Among other interesting points, Dr. Doberck has remarked that 

 he has never found any indications of secondaries dependent on a 

 primary cyclone ; that the vertical succession of upper currents is the 

 same as obtains in higher latitudes ; and that the incurvature of the 

 wind is less in front than in rear of a typhoon. The last is identical 

 with what Meldrum has found in the South Indian Ocean, but the 

 contrary of what usually occurs in Great Britain. Dr. Doberck also 

 considers that the incurvature of the wind in a typhoon decreases as 

 the depression recedes from the equator. 



There are many observations to the effect that the central calm 

 does not coincide with the minimum of the barometer ; but nothing 

 has yet been remarked with reference to trough phenomena. 



Thunder] and lightning do not occur in the heart of the typhoon ; 

 but 600 to 800 miles to the S. or S.W. of the centre thunderstorms 

 may be experienced. 



Japanese Typhoons. 



From Hong Kong the author proceeded to Tokiyo, in Japan, to 

 study the transitional district between tropical and extra-tropical 

 cyclones ; and through the courtesy of Mr. E. Knipping and Mr. Y. 

 Wada, he succeeded in obtaining most valuable information. 



The result of all his researches may be briefly summarised as 

 follows : — 



