Jtme 26, 1879] 



NATURE ZO 



195 



at elevations now occupied only by the yak and similar 

 mountain forms. 



In reference to the greater richness of the Siwalik 

 fauna, as contrasted with the Indian fauna of the present 

 day, he quotes -with approval the suggestion of Mr. 

 Wallace, that a sweeping reduction was brought about by 

 the cold of the glacial period. Of the influence of this cold 

 in India, there are abundant proofs in the great extension 

 of the Himdlayan glaciers, for instance, in Sikkim and 

 Kashmir, down to 6,000 feet and 8,000 feet above sea- 

 level ; and in the Naya hills of Assam, whose greatest 

 elevation does not exceed 10,000 feet, in the large 

 moraines at 4,500 feet, described by Col, Godwin Austen. 



The oldest proofs of man's occupation hitherto met 

 with in India, arc a chipped axe or scraper, in the alluvial 

 (post-pliocene) deposits of the Narbada, associated with 

 remains of Urstis, Elephas, Rhinoceros, Hippopotamus, 

 Teiraprotodon, and Bos, all of extinct species ; and a 

 flake, apparently of human manufacture, in the Godavari 

 gravels of similar age. Quartzite implements of the 

 palceolithic type are abundant in the laterite gravels of 

 Madras, but these are probably of later date. Axes of 

 neolithic type have as yet been met with only on the 

 surface, most abundantly in the Banda district of the 

 North-West Provinces. 



The Manual is illustrated by twenty-one admirably 

 executed lithographed plates of characteristic fossil forms, 

 and a few woodcuts of sketches and sections. Its utility 

 for purposes of reference is rendered all that can be 

 desired by a copious and well-arranged index. We con- 

 fidently hope that the publication of the work will give an 

 impulse to the advancement of Indian geology by adding 

 largely to the number of non-professional workers, a class 

 which has hitherto been singularly wanting in India, 

 despite the examples of such men as Carter, Forbes, New- 

 bold, Strachey, and Hislop. H. F. B. 



/ LETTERS TO THE EDITOR 



[ The Editor does not hold h imself responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, or 

 to correspond with the writers of, rejected manuscripts. No 

 notice is taken of anonymous communications. 



[ The Editor urgently requests correspondents to keep their letters as 

 short as possible. 2 he pressure on h is space is so great that it 

 is impossible othenvise to ensure the appearance even of com- 

 munications contaitiing interesting and novel facts .'\ 



Prof. Clifford's Mathematical Papers 



Having, at the request of Mrs. Clifford and Dr. Spottis- 

 woode, undertaken the editing of the late Prof. Clifford's 

 mathematical papers, I am anxious to secure the co-operation of 

 all mathematicians who are interested in the matter. Prof. 

 Clifford does not appear to have been in the habit of widely 

 distributing copies of his writings, so I have found of many of 

 them a great number of copies, whilst of others I have not come 

 .icross a single one. 1 will fir^t state what I have : — 



All papers in the Phil Trans. , in the Proceedings of the 

 London Mathematical Society, in the Messenger of Mathematics, 

 in the Manchester Transactions, in the Cambridge Philosophical 

 Society's Journals, in the South Kensington Handbook, in the 

 Mathematical Reprint from the Educational Times. 



Of the papers in the Quarterly Journal of Mathematics I have 

 only §§ i-ii, 17-23, of the Analytical Metrics. I should be glad 

 also to have a copy of the ^"(rar/cw/ for August 15, 1873, and 

 information about "Lecture Notes" on Geometry. These last 

 are lithographed and are comprised in twenty -six articles (?all), 

 of which I lack one page, containing § ig-2I. I need hardly 

 add I shall be glad to receive any other papers (mathematical) 



which are not contained in the above-named journals. The 

 Nature article (translation of Riemann) I have. I have ^Irs. 

 Clifford's permission to distribute the author's copies of her late 

 husband's papers to mathematicians who may wish to have 

 them. R. TuCKER 



27, Cantlowes Road, Camden Square, N.W. 



Pine-Pollen mistaken for Flowers of Sulphur 



The following paragraph appeared in the Times of June 

 16:— 



" During the past week, after heavy rain, a thin film of 

 sulphur has been observed at Windsor, Slough, and in the neigh- 

 bourhood generally, to settle upon the surface of rain-water 

 caught in butts and cisterns. The phenomenon at first did not 

 attract much attention, but being observed on different occasions 

 it has given rise to muck speculation as to the cause of it, there 

 being no manufactures in the neighbourhood at all likely to have 

 produced it. It has been suggested that a sulphureous vapour 

 may have been wafted to this country by the recent south-east 

 winds, and arrested and deposited in the rain." 



The supposed "sulphur rain," a fine yellow dust, was the 

 cause of great excitement among the country people in this 

 neighbourhood. It was first observed on the afternoon of Sunday, 

 June 8, after a remarkably heavy shower, and much disturbed 

 the inhabitants of some of the villages round Eton, who farcied 

 that it smelt "awful like brimstone," of which its yellow colour 

 was somewhat suggestive. In some places it gave rise to such a 

 feeling of fright that the people were afraid to go to bed, 

 thinking that the judgment day was at hand ! Two or three 

 days afterwards there was another "sulphur" shower, and I 

 collected a quantity of the dust with my pupils, who were at 

 work with me in my laboratory at the time. One of them, H. 

 Bury, immediately recognised its resemblance to the pollen of 

 Pinus pinaster, with which he is familiar from its abundance in 

 the neighbourhood of his home at Bournemouth ; and we have 

 none of us any doubt but that this so-called sulphur is the pollen 

 of this tree cr of the Scotch fir, Pinus sylvestris, both of which 

 are common in Windsor Forest. Two of the Windsor doctors, 

 both practised microscopists, at once came to the same conclusion ; 

 but a local chemist and druggist is said (on good authority) to 

 have supported the sulphur theory. This, perhaps, accounts for 

 the rather positive statement by the Windsor correspondent of 

 the Times as to the nature of the deposit, and also for the 

 suggestion he refers to respecting its origin, which explains the 

 phenomenon in a manner that is certainly more curious than 

 probable, from a chemical point of view. I hear that the "sul- 

 phureous vapour" is supposed to have been "wafted to this 

 country," after escaping from Etna during the recent eruptions, 

 which fortunately occurred at just the right time to give apparent 

 probability to the sulphur theory. 



Thinking that such a remarkable phenomenon should not be 

 allowed to pass unnoticed, I sent a short note to the Titnes of 

 the 17th inst., stating the real (pollen) nature of the yellow dust, 

 hoping that this would set the matter at rest and dispel the 

 superstitious fears of the rustics. I was therefore greatly sur- 

 prised, a few days afterwards, at receiving a letter from an 

 F.R.G.S. residing near Carlow, in Ireland, who had seen my 

 note in the Times, but nevertheless spoke of an "extensive fall 

 of sulphur " in his neighbourhood. He was good enough to 

 inclose me a "specimen of its incrustations" on a dead leaf, and 

 said that " till yesterday's heavy rains any quantity of leaves 

 like that I send you might have been gathered, and the edges of 

 the pools of water were heavily mcrusted with pure sulphur." 

 He added that he thought I should not find the deposit to be 

 "the produce of Pinus pinaster. " This, of course, was rather 

 startling, for I naturally supposed that no one would write so 

 confidently who had not satisfied himself by chemical tests and 

 by microscopical examination as to the truth of his statements, 

 especially after hearing of the mistake which had been made in 

 England. A glance at the deposit under the microscope, how- 

 ever, revealed its true nature — pine- pollen again ! 



I wrote accordingly to my informant, telling him this and 

 sending him some pollen taken directly from the tree, so that he 

 might recognise its similarity to the " pure sulphur " he so kindly 

 sent me. I hope that by this time he has done so. 



The above facts are of interest, partly as affording an excellent 

 illustration of the transportation of pollen by the wind, and 

 partly because they show how ready some people are to attribute 

 an almost miraculous origin to anything a trifle out of the com- 



