2S 



NA TURE 



[June 9, 1892 



The more distant localities did not, of course, view the same 

 edge as those nearer, but one which must have been rather nearer 

 them and lower down. Thus they are subject to a positive and 

 a negative source of error, which cannot be well estimated, but 

 virhich fortunately tend to neutralize each other. 



The resulting height is unexpected, but the records agree so 

 nearly as to leave little doubt of its substantial accuracy. Mr. 

 Backhouse's measurements were made merely for altitude and 

 an hour later, but the cloud-shift was so slight that it has been 

 included. J. Edmund Clark. 



A Dust Storm at Sea. 



A FEW days ago, while returning to Tokio from the southern 

 part of Japan, I joined the s.s. Yokjhania Alartt, which, whilst 

 crossing; from Shanghai to Nagasaki had passed through a 

 curious dust storm. Small quantities of the dust were yet to be 

 seen in sheltered corners of the vessel. The commander, Cap- 

 tain R. Swain, who gave me a specimen of the material, told me 

 that on April 2, when about 95 miles west by south of Naga- 

 saki (long. 128° E., lat. 32° 20' N.), at about 6 p.m. the sun 

 appeared quite yellow. The atmosphere was moist, and ren- 

 dered everything upon the deck of the ship quite damp. The 

 precipitated moisture was yellowish, and as it dried it left an 

 extremely fine powder. For two days previously the wind had 

 been blowing west-south-west, or from China. Nothing was 

 felt in the eyes, and if the ship had not been covered with 

 yellow powder, the phenomenon would have been regarded as an 

 ordinary but peculiarly coloured fog. 



The yellow atmosphere was noticed during the afternoon of the 

 2nd. At midnight the wind changed to north-west-^that is, 

 from Corea. The probability, however, is that the material 

 cf.me from the loess plains of China. In Nagasaki, which is 

 390 miles from the coast of China, a yellow sun was noticed on 

 the morning of the 2nd ; and during the day, whilst dust was 

 being precipitated, the appearance of the atmosphere was com- 

 pared to that of a London fog. 



On April i there was a fall of dust in the neighbourhood of 

 Nawa in Okinawa-ken, and on the 2nd dust fell in Gifu — the 

 district where the recent great earthquake took place. The 

 P. and O. s.s. Verona, which left Hong Kong on April i, 

 experienced ihe same phenomenon as the Yokohama Maru, the 

 vessel being covered with a fine dust, which, when suspended in 

 the atmosphere, gave rise to so much haza that land was not seen 

 until reaching Nagasaki. On April 3 a yellow sun was seen in 

 Yokohama, but I am not aware that any dust was observed. 

 Roughly speaking, it therefore seems that on April 2, at a 

 distance of from 200 to 400 miles from the coast of China, there 

 was a cloud of dust which may have been over 1000 miles and 

 possibly 2000 miles in length. Dr. B. Koto, who examined a 

 specimen, tells me that the particles are chiefly felspar, but there 

 is a little quartz and shreds of plants. John Milne. 



Tokio, April 23. 



Submerged Forest, 

 During a recent visit to an East Lincolnshire seaside place, 

 Mabelthorpe, the remains of a submerged forest were pointed out 

 to me plainly visible at low water. On closer inspection, the 

 stumps of fallen trees, firmly embedded in the clay from one to 

 twenty inches above the surface could be traced along the low- 

 water level. I should be much obliged if any reader could fix a 

 date at which the forest was growing. Does it not prove a sub- 

 sidence of land in the neighbourhood ? M. H. M. 



Carnivorous Caterpillars. 



I SHOULD like to know if it is a known fact that some cater- 

 pillars are carnivorous, eating their own kind, and small ones of 

 another kind ? I have found on a lime-tree on our lawn, six 

 caterpillars, two of which have done so. 



One of them has (though there was plenty of food, as I had 

 only taken it from the tree a few minutes) eaten one of its own 

 kind about three-quarters its own size ; and later on in the day a 

 small green looper (off the lime-tree), which was in the same 

 box. A second has eaten two small loopers. The other three 

 I only found to-day, and they are not as large as those which 

 had eaten their fellows. 



I cannot find a description of this caterpillar in " Das Buch 

 der Schmetterlinge " (Lutz), which I use. 



They are of a bright green, the colour of the young lime 

 leaves, with a narrow white line down the back and along each 



NO. I 180, VOL. 46] 



side half-way down, and a broader one lower down. Between 

 this and the narrow side-stripe are three very small black spots ; 

 between the back line and the narrow side-line, are two black 

 spots, to each segment. Each spot has a white edge. On the 

 first two segments the upper two spots are one under the other ; 

 but on the rest are side by side. The three spots form an L, 

 with the two lower ones very near, or on the broad side-line. 



They have eight prolegs, as well as the two suckers at the 

 back. They appear very irritable, and swing their heads from 

 side to side when touched, and apparently nip other caterpillars 

 which dare to touch them in any way. 



I may also mention that there are three very fine specimens of 

 the Red Admiral ( Vanessa Atalanta) in our garden to-day and 

 yesterday. Juliet N. Williams. 



Blackbrook, Bickley, Kent, May 29. 



THE HURRICANE IN MAURITIUS. 



THE devastation caused by the hurricane in Mauritius 

 was so terrible that it was hardly to be expected 

 the Observatory would be spared. We are glad to say, 

 however, that it suffered no damage ; and all meteoro- 

 logists will congratulate themselves that the well-known 

 Director, Mr. Meldrum, was able without delay to prepare 

 an account of the storm. The account is printed in the 

 special overland edition of The Merchants and Planters 

 Gazette, May 11. We here reproduce it : — 



" Saturday, April 30. 



" The hurricane which raged for a few hours yesterday, 

 April 29, has in many respects been unprecedented in 

 Mauritius, 



" Never till now has the island been visited by a hurri- 

 cane at any time between April 12 and December i. 

 Hitherto the hurricane season of Mauritius has been 

 supposed to begin on the latter and to end on the former 

 day, and till yesterday there has been no exception to 

 the rule, 



" Nor was there any sign of danger till yesterday, when 

 the barometer began to fall rapidly and the wind to in- 

 crease to a heavy gale. The suddenness, rapidity, and 

 extent of the changes which took place in a few hours 

 are unparalleled in the annals of the colony, 



" The following table will for the present sufifice to 

 convey some idea of the changes which took place in the 

 barometric pressure and the direction and velocity of the 

 wind from 9 a.m. on the 24th to 9 p.m. on the 29th : — 



