1884.] W. F. Sinclair — Notes on Monsoon Waves. 163 



Mr. R. D. Oldham asked whether the " Peepsa " was the same as 

 the " Poto " of the North Western Frontier. He explained the effects 

 of the bite of the latter, and inferred from the drawing exhibited that 

 the two insects were the same. 



The Natural History Secretary replied that the genus Simulium 

 was a Palasarctic form, and that the same or closely allied species in all 

 probability extended all along the Southern slopes of the Himalayas, 

 when the Palsearctic form was inter digitated with the Oriental. 



3. Notes on the monsoon waves on the coast of Alibagh, south of 

 Bombay Harbour, taken during the Monsoon of 1884. — By W. F. Sinclair, 

 1st Assistant Collector, Kolaba. Communicated by H. F. Blanford, 

 F. R. S. 



The Alibagh taluka lies immediately south of Bombay Harbour ; 

 and its coast for about twenty miles receives the full force of the S. W. 

 Monsoon. The bottom is sand and mud, with frequent reefs, and sloping 

 gradually to the west. The worst sea is between three and four fathoms 

 of water ; inside that limit the surf seems to lose its power as it nears 

 the shore ; outside it is the deep water swell. There are at Alibagh two 

 life-boats, which are constantly out in all weathers. The first the 

 " Bhotuani " carries her mainpeak 24 feet above the load water line, 

 and the other, the " Allen Shuttleworth" 33 feet above. The Bhowani's 

 sail is frequently becalmed and flaps between the seas ; the Shuttle- 

 worth^ has only been observed to do so once this year, though she 

 was out in worse weather than the Bhowani. The uppermost 3 or 4 feet 

 of the sail, though holding wind, will not prevent the rest from flap- 

 ping, as is shown by the sail flapping when the flag flown at the peak 

 (of three feet hoist) flies free. The flag itself is sometimes becalmed, 

 but not so often as the sail. The conclusion is that waves of about 

 20 feet in total height, that is, 10 feet above the general level of the 

 water, are common ; and waves of about 24 not uncommon ; but waves 

 of 30 feet very rare. These observations, however, apply only to the 

 dangerous belt between and about 3 and 4 fathoms of water (outside 

 and inside of which even the Bhowani's sail seldom flaps) and on it 

 only to the big waves commonly called " ninth waves." It has not been 

 found in the course of these observations that the ninth waves are the 

 worst ; nor indeed that any particular number or interval of time can 

 be fixed ; though it might naturally be expected that some regularity 

 would be found when the wind is pretty steady. Sometimes three waves 

 together seem to be bigger than the others. 



A second means of guessing at the height of the waves was 

 employed. At a little over three nautical miles from a fixed point on 



