1848.] Sixteenth Memoir on the Law of Storms. 525 



SUMMARY. 



As there are evidently the records of two or three separate storms in 

 the foregoing documents, I shall begin, in explaining the reasons for 

 the tracks assigned to them, with that which is first in order of date, 

 as well as to the Northward on the Chart, which is the Orient's 

 hurricane. This ship was evidently gradually approaching a zone of 

 threatening weather from the 24 th of March, or rather from the p. m. of 

 the 23rd. On the 25th the Barometer had been and continued steadi- 

 ly falling, and by 8 p. m. on this day she had " a gale" from the E. \ 

 S., and hove to on the port tack. Simpiesometer falling from 29.40 

 at 4 p. m. to 29.20 at midnight ; the Barometer from 29.50 to 

 29.35. " Thick weather to the Eastward" is also noted. There is no 

 doubt then that by this time she was involved in the vortex of which 

 the centre bore about N. by W. from her at midnight. By the rule 

 given at page 199 of my new work, the Sailor's Horn Book, the fall 

 of the Simpiesometer being taken as the average one,* of about *025 per 

 hour, the distance of the centre from her between 8 p.m. and midnight, 

 or say at 10 p. m. may have been about 200 miles, which would place 

 it in about Lat. 8° 30' S., Long. 77° 18 ; E., and it was either travelling- 

 down much faster than it did on the following days, or this distance is 

 too much ; but in either case the rule holds good, because the seaman 

 should never allow less than 10 or 12 miles per hour. If we suppose 

 the track somewhat curved the distance is 215 miles to the position of 

 the centre at Noon on the 26th, which for the 14 hours from 10 p. m. 

 to Noon is 15^ miles per hour. Hence if the distance was too much 

 the rate of travelling assigned in usual cases corrects it sufficiently for 

 all practical purposes. 



From this hour, 10 p. m. we find the wind gradually veering, first as 

 far as to the Northward of E. by N. as N. E. by E. for a couple of 

 hours, then again to the Eastward, and gradually round to South at 

 noon on the 26th. This is while the ship was making an average 

 drift to the S. W. by W. and W. S. W., and would indicate a slight 

 veering of the track (or a somewhat eccentric direction of the wind :) 

 but it is clear that it passed close to the Eastward of the Orient , and 

 very rapidly, by the veering from East at 10 p. m. to South at noon, or 



* Because the Barometer talc was for tins time, 4 p. an. to 10 p. iu. against the fall ; 

 i. e. it was the time of the rise. 



4 b 2 



