i6 



NATURE 



[May 6, 1875 



METEOROLOGY, ETC., IN MAURITIUS 



THE following letter from Mr, C. Meldrum, dated 

 " Observatory, Mauritius, April 2," to a friend in 

 England, gives some interesting data tending to prove a 

 connection between solar activity and the state of the 

 weather. With his new instruments we may hope soon 

 to have some most important results. 



"Since December last the colony has been suffering from 

 drought, and there is very little appearance of a favourable 

 change. February has been the driest month since systematic 

 observation commenced in 1852, and the rainfall for January 

 and March has been far below average. If the present state of 

 things continue long, the island will be hard up for witer. 



' ' Coincident with this drought there has been, as usual on such 

 occasions, a great falling off in the number and violence of 

 cyclones in the Indian Ocean. We copy here the log-books of 

 all vessels arriving in port from India, Australia, the Cape, 

 England, &c., so that no great storm can take place over the 

 greater part of the ocean without our getting more or less infor- 

 mation about it. Well, the hurricane season is nearly over, and 

 we have heard of only two storms, one on the 24th of January 

 away to the northward of us, and one on the 7th of March, away 

 to the eastward of us, and neither of them seems to have been 

 extensive or very violent, only two vessels having been involved 

 in each. The season thus bears a remarkable contrast to the 

 corresponding periods for 1 871, '72, and '73, and furnishes another 

 instance of the now oft-observed fact that when Mauritius suffers 

 from drought the Indian Ocean is almost free from hurricanes. 

 The neighbouring island of Reunion has fared as badly as 

 Mauritius, and the log-books furnish evidence that the drought 

 has prevailed over a wide area. 



" The S.E. trade-wind has been blowing from S.E.to E. and 

 E.N.E. almost without interruption during the last three months, 

 and the barometer been unusually high and steady for the season, 

 thus showing that from some cause or other the belt of calms and 

 variables between the S.E. trade and the N.W. monsoon has 

 not advanced so far to the south as it did in the years 1871-74. 



" It is only now that I am enabled to keep a continuous record 

 of the sun-spots, the photo-heliograph having been put up a fort- 

 night ago, and being at work only for a week ; but from obser- 

 vations made directly, as often as possible, it would appear that 

 there has been a great falling off in the number and magnitude 

 of the spots. If this is the case, then we have, as on many other 

 occasions, a decrease of spots, a decrease of cyclones, and a de- 

 crease of rain all at or about the same time. 



" Our latest telegraphic news, via India, states that severe cold 

 prevailed throughout Europe. It would be very interesting to 

 know the conditions of weather for the whole habitable globe 

 during the last three months. Comparative meteorology — in- 

 cluding the sun's — can alone throw light on the nature of the 

 relations subsisting between weather changes and variations of 

 solar activity. 



"Although the sun-spots decreased considerably in January and 

 February, yet one or two pretty large ones appeared towards the 

 end of February, and on the 27th of that month, between i and 

 7 P.M. we had (for this latitude) a remarkable magnetic storm. 

 I fancy next mail will bring us news of auroras and magnetic 

 storms having been observed in different parts of the world at 

 that time. We had no aurora here, but on the 25th, 26th, 27th, 

 and 28th there appeared, shortly after sunset, long beams of light 

 radiating from a point near the horizon at E. by N. (nearly 

 opposite the sun). This of course is easily explained without 

 an aurora or any fitful outburst on the sun, but I have noticed 

 that these radiating beams, which are sometimes very gorgeous, 

 and occasionally radiate from points near the poles, are much 

 more frequent in some years than others — which may arise from 

 different states of the vapour and clouds. Dr. Lyall, who took 

 a series of observations in Madagascar about forty-five years ago, 

 makes mention of them, and describes them under the name of 

 Aurora. 



" Wc have all the instruments at work now, except the thermo- 

 graph, which has not arrived. I have been so much occupied 

 with the putting up of the instruments and removing into the 

 new Observatory, that I have had very little time for anything 

 else. I wished to send to the Royal Society some papers, but I 

 could not manage to get sufficient leisure to prepare them. In 

 a short time we shall be in train, and I hope to resume the sub- 

 ject of periodicities, &c." 



SCIENTIFIC SERIALS 



The current number of the Quarterly Journal of Microscopical 

 Science commences with an account by Mr. Wm. Archer of a 

 new freshwater sarcodic organism, named by the author Chlamy- 

 domyxa labyrinthuloides, which is illustrated by a superb folio- 

 sized coloured plate, as well as an octavo one. The species is 

 shown to be closely allied to Labyrinthula of Cienkowski. The 

 matrix is enclosed in a multilaminate cellulose envelope, which 

 at times appears to burst and give exit to protoplasmic contents, 

 which emerge in an arborescent manner with hyaline prolonga- 

 tions, along which small fusifoi-m protoplasmic masses travel. — 

 Rev. M. J. Berkeley gives a short account of the Thread Bliglit 

 of Tea, in which he describes the fungus producing it, although 

 he is unable to name it because he has not had an opportunity 

 of examining the fructification. — Mr. P. Kidd draws attention to 

 the occurrence of spontaneous movement in the nucleoli of the 

 epithelium of the frog's mouth. — This paper is followed by an 

 excellent and illustrated account of the structure of the Pacinian 

 corpuscles, considered with reference to the homologies of the 

 several parts composing them, by Mr. Edward Schiifer, in which 

 it is shown — assuming an ordinary nerve fibre to consist of the 

 axis cylinder in the middle, surrounded by, first, the medullary 

 sheath, or white substance ; secondly, a delicate layer of proto- 

 plasm containing nuclei ; thirdly, the primitive sheath (of 

 Schwann) ; and lastly, the numerous laminae of the neurilemma, 

 which, however, encloses a layer of finely filamentous connective 

 tissue — that the coats of the Pacinian are the layers of the neuri- 

 lemma ; that the sheath of Schwann surrounds tlie core, this 

 latter being an expansion of the protoplasmic substance ; that 

 the medullary sheath, if not retained as such, disappears, and 

 that the axis-cylinder becomes the central fibre. — Mr. A. W. 

 Bennett gives an account of modern researches into the nature of 

 yeast, specially noticing those of Reess and Cienkowski. — Prof. 

 Lankester has a paper of special theoretical importance, on the 

 Invaginate Planula, or Diplobastic Phase of Paludina vivipara ; 

 in which, after proposing the name "blastopore" for the orifice 

 of invagination of those Planulae which exhibit it, he proposes a 

 a classification of Planulse, which helps to simplify this intricate 

 part of embryonic history. He divides Planulte into two groups : 

 Delaminate Planulas, in which there is no invagination, but a 

 splitting of the blastosphere to form the endo- and ecto-derm ; 

 and Invaginate Planulce, which may be etubolic, or have no food- 

 yelk ; or epibolic, possessing a "residual yelk." The Hydrozoa 

 and Calcareous Sponges have delaminate planula; ; Amphioxus, 

 Ascidians, many Mollusca, Sagitta, Echinodermata, and many 

 Vermes have embolic invaginate planula; ; whilst in the third 

 group are included many Mollusca, many Vertebrata, the Cteno- 

 phora, certain Vermes, and certain Arthropods. — Mr. H. C. 

 Sorby describes the absorption spectrum of Bonellia viridis, and 

 draws attention to a most striking point, namely, that there seems 

 to be a constant ratio between the wave-lengths of the different 

 bands in these spectra. — The number contains its usual excellent 

 quarterly chronicle, notes, &c. 



Ta^ Journal of the Chemical Society (March 1875) contains 

 the following papers, besides a large number of abstracts from 

 other serials, already noticed in Nature : — The formulae of the 

 alums, by S. Lupton. The author briefly states the formulae 

 given to the alums before they were finally designated as 

 A' B"'2S04. 12H2O (where A stands for an alkali metal and B 

 for a metal of the iron group). At present some chemists use 

 this formula, while others double it into A2'B2"'4S04.24H20. 

 The cause of this variety of usage rests in the uncertainty attach, 

 iug to the atomicity of alumium ; this metal appears as a tetrad 

 when combined with chlorine, bromine and iodine, but as a triad 

 in its methyl and ethyl compounds. The author tried to obtain 

 certain bodies similar to the alums in constitution, but differing 

 in the number of molecules of water which they contain ; the 

 latter have often served to establish the formula of salts. Experi- 

 ments were made with iron and ammonium alum, aluminium and 

 potassium alum, and alumium and ammonium alum ; these 

 experiments are described, and the author arrives at the conclu- 

 sion that the doubled formula as above is the correct one, as it 

 seems that upon dehydration the residue R2'R2'''4S04 remains 

 unaffected, and exists therefore in the ordinary alums in com. 

 bination with 24 molecules of water. — On the colour of cupric 

 chloride, by Walter Noel Hartley. This salt is almost invari- 

 ably described as being of a green colour, but the author has 

 found that the salt is only green as long as there is a trace of 

 moisture about it ; as soon as the salt is quite dry its crystals are 



