June 9, 1892 



NATURE 



129 



" In the above table the fall or rise in the barometric 

 pressure is corrected for the daily variation, and from 

 9 a.m. on the 24th to 9 a.m. on the 29th the mean hourly 

 velocities of the wind are given, whereas from 10 a.m. to 

 5 p.m. on the 29th the rates of the velocity per hour are 

 given as obtained from observations taken during in- 

 tervals of two to five minutes. 



" It will be seen that at 2 p.m. on the 29th the baro- 

 meter was at 27-990 inches ; that from noon to 2 p.m. 

 it fell I -045 inch ; that from 3 to 5 p.m. it rose roi2 inch ; 

 and that from 5 to 9 p.m. it rose '660 inch. The abso- 

 lutely lowest pressure was 27-961 inches at 2.30 p.m., 

 which is the lowest on record in Mauritus. 



*•■ From 9 a.m. on the 28th to i p.m. on the 29th the 

 mean direction of the wind did not vary much, but it 

 occasionally showed a tendency to veer towards north, 

 being at times from north-east by north to north-north- 

 east. Between i and 2 p.m. it on the whole veered to 

 north, and between 2 and 3 p.m. to west-north-west, 

 oscillating considerably, and soon after settling down at 

 west-south-west. 



"After 1 1 a.m. the velocity of the wind increased much, 

 being at i p.m. at the rate of 96-5 miles an hour, and at 

 1.20 at the rate of 104 iniles. But from 1.25 to 2.30 p.m. 

 there was a lull, the velocity decreasing to the rate of 43 

 miles an hour at 2.33 p.m. It then bej:an to increase 

 again, and at 3.47 p.m. was at the rate of 121-2 miles per 

 hour, but it soon began to abate, being at the rate of 72 

 miles at 5-20 p.m., 60 miles at 6 p.m., 47 miles at 7 p m. 

 and 26 miles at 9 p.m. By this time the weather was 

 fine, the sky partially clear, and here and there stars 

 shining brightly. 



" Seeing that from 9 am. on the r4th to 9 a.m. on the 

 27th the barometer had fallen from 30059 to 29-903 

 inches, and that the wind, though light, had veered from 

 east-south-east half south to east by south, a note was 

 sent to the newspapers on the latter day, stating that 

 there was heavy weather to the northward, and that it 

 had existed since the 24th ; which, as usual in such cir- 

 cumstances, meant that there were indications of a 

 cyclone away to the northward and that it was travelling 

 from north-eastward to south-westward. 



"But the wind having by 9 a.m. on the 28th reached 

 north-east by east, and the barometer being higher on 

 the 27th at the same hour, there was no apprehension ; 

 and in the afternoon of the 28th, the wind being still 

 moderate from north-eastward, and the barometer falling 

 at the rate of only 0003 inch per hour, it was announced 

 that there was no fear. 



" As already stated, it was only on the 29th that the 

 conditions became unfavourable, and at 9.40 a.m. a tele- 

 gram was despatched announcing that the barometer was 

 falling at an accelerating rate. 



"Other telegrams, despatched at 11 a.m., announced 

 that the velocity of the wind was at the rate of 52 miles 

 an hour in the squalls, and that probably it would not 

 exceed 56 miles an hour. Soon afterwards the telegraph 

 wires were broken, and all communication ceased. 



" The barometer continuing to fall at an accelerating 

 rate, and the mean direction of the wind being nearly 

 constant, it was inferred that the centre of the depression 

 would, contrary to long experience (the wind being from 

 north-east) pass over the island, and that the wind would 

 then come from nearly the opposite direction. 



" The centre, however did not pass over the Observa- 

 tory, but over a point about six miles to the westward of 

 it, and apparently from that point it travelled across the 

 island on an east-south-easterly course. 



"As a rule, when the wind is from north-eastward, 

 there is scarcely any danger of a hurricane in Mauritius. 

 All our great hurricanes have commenced, not with a 

 north-easterly, but with a south-easterly wind ; and this 

 is why, when the wind was from north-east by east at 

 1 1 a.m. yesterday, and the barometer at 29-338, it was 



NO. 1180, VOL. 46] 



considered probable that the velocity of the wind would 

 not exceed 56 miles an hour. On February 12 last, the 

 barometer fell to 29325, and the greatest velocity of the 

 wind was 47-5 miles per hour from north-east, the baro- 

 meter soon afterwards rising and the wind decreasing. 



" There are, apparently, only two ways of, in a measure, 

 accounting for the passage of the centre of a hurricane 

 over the island yesterday from west-north-westward to 

 east south-eastward Firstly, the cyclone which had been 

 travelling to the northward and north-westward of the 

 island on a south-westerly course, from the 24th to the 

 27th, recurved to the southward and south-eastward ; or 

 secondly, a small secondary cyclone, which was generated 

 in the south-east quadrant of the larger cyclone, travelled 

 to the east-south-eastward, and bore down on Mauritius. 

 The latter is perhaps the more probable hypothesis ; for 

 the small but violent hurricane of yesterday, with respect 

 to its extent, duration, &c., exhibited the characteristics 

 of a local atmospheric disturbance. 



" On the night of the 27th and morning of the 28th there 

 was a great deal of thunder and lightning, and also 

 frequent lightning during the night of the 28th. But the 

 hurricanes of Mauritius are seldom, if ever, immediately 

 preceded by thunder and lightning. 



" It may be stated, also, that from the 25th to the 29th 

 there were from five to six groups of sun-spots, indicating 

 a considerable increase of solar activity ; and that from 

 the 25th to the 28th there were large magnetic disturb- 

 ances, the portion of the sun's disk on which there was a 

 very large group of spots on February 12 being again 

 on or near the sun's central meridian. ' 



"C. Meldrum." 



PROFESSOR JAMES THOMSON. 



pROF. JAMES THOMSON, who died on May 

 -*■ 8, after a few days' illness, the result of a 

 chill, was born in Belfast in 1822. He was the son of 

 James Thomson, who was then Lecturer on, and afterwards 

 Professor of, Mathematics in Belfast, and subsequently 

 became Professor of Mathematics in Glasgow University. 

 The father was a highly successful teacher and original 

 investigator in mathematics, and was the author of many 

 important school books. One of these books was, thirty 

 years ago, still the recognized text-book on arithmetic in 

 Ireland, and in all probability still retains its position. It 

 was referred to by its very well-known title the "Thomson," 

 by Prof. Tyndall in his British Association Address in 

 1874. We do not need the assurances of contemporaries, 

 which are plentiful, that the two boys, James and 

 William Thomson (now Lord Kelvin), made brilliant 

 progress in their father's subject, and exhibited, even in 

 early days, that combination of inventive genius and pains- 

 taking effort for accuracy, which have been their great 

 characteristics since. James took his M.A. degree at 

 Glasgow, served an apprenticeship under Sir William 

 Fairbairn, and practised in Belfast as an engineer. He 

 held the appointments of engineer to the Belfast Water 

 Commissioners and to the Lagan Canal Navigation 

 Works. In 1857 he became Professor of Civil Engineer- 

 ing in Queen's College, Belfast, and his Belfast pupils are 

 to be found occupying high positions in every part of the 

 world. He succeeded Rankine in Glasgow in 1872, and 

 resigned the Professorship at Glasgow in 1889 because 

 his eyesight was failing. He became a Fellow of the 

 Royal Society in 1877. He received the honorary degrees 

 of D.Sc. from the Queen's University of Ireland, and of 

 LL.D. from Glasgow and from Dublin. In 1853 he 

 married the only daughter of the late Mr. William John 

 Hancock, J. P., of Lurgan, Co. Armagh, and it is a 

 pathetic circumstance connected with his death, that she 

 and one of his daughters survived him only a few days. 

 He leaves a son and another daughter. 



