126 



NATURE 



[March 31, 1910 



parishes, called Taluks, and the rainfall is gauged at the 

 chief town of each Taluk. The mean of these is taken as 

 the rainfall for each District. From the average monthly 

 rainfall of each District for the past thirty-nine years I 

 have found the C.G., also for the year 1908, and they 

 are given for comparison : — 



Province... 77 ... 36-79 ... 768 .. 29-94 ... 6-91 



The Shimoga and Kadur districts each include three 

 stations where the rainfall is enormously greater than at 

 the other stations; yet though the thirty-nine-years' 

 average annual rainfall for six of the Shimoga Taluk 

 stations is only 35-78 inches, and for the three stations 

 of great rainfall it is 128-24 inches, I find that the mean 

 position of the C.G. is 7-28 for these three stations, while 

 for the whole nine stations it is 7-34. In the same 

 Shimoga District there are, besides the nine Taluk stations, 

 fourteen additional rain-gauge stations, among which are 

 Agumbi, with a mean yearly rainfall of 333-17 inches, 

 Aralagode, with mean of 237-79 inches, and Karur, with 

 mean of 115-79 inches, and I find the C.G. for these is 

 at 7-29, 7-21, and 7-13 respectively. 



It is to be noted that the great deficiency of rainfall 

 throughout Mysore Province as a whole for the year 1908 

 is indicated, not only by the diminished yearly totals, but 

 by the displacements of the C.G. for each District and for 

 the whole Province. This means, of course, that the 

 deficiency was in the " latter rains " — or those for the 

 north-east monsoon — but the important thing is that we 

 have a si'mple numerical measure, by combining the dis- 

 placement of the C.G. and the total rainfall defect, of the 

 real rainfall deficiency for the year. Thus while the rain- 

 fall average for the whole Province was 18-6 per cent, less 

 than the yearly normal, the deficiency of the rain-moment, 

 as we may call it in the language of mechanics, 

 was 26-8 per cent., which agrees better with the agri- 

 cultural effect. 



This has led me to examine Dr. H. R. Mill's " British 

 Rainfall " for 1908, and the results of working out the 

 C.G. for a large number of stations, and for the 1908 

 mean rainfall of England, Scotland, and Ireland, are 

 interesting. The position of the C.G. for the monthly 

 mean rainfall of 122 stations in England and Wales is 

 6-54, of 55 stations in Scotland 6-37, of 53 stations in 

 Ireland 6-72, and of 230 stations in the whole British 

 'sles 6-55. For Greenwich, with rainfall 2378 inches, 

 it is 6-48 ; for Borrowdale (Cumberland), with rainfall of 

 127-38 inches, it is 6-54; for Glenquoich (Inverness), with 

 107-40 inches, it is 6-21 ; for Kenmare (Co. Kerry), with 

 7o-qi inches, it is 6-59. 



From the Journal of the Scottish Meteorological Society 

 for 1908 I find the following results : — 



Year's p. /-. 



Rainfall. '--^- 



Means of the eight principal towns of Scotland 33*05 ... 6-54 



Means for all Scotland for 1908 37*55 --- 6-48 



Means for all Scotland for fifty years (1856- 



1905) 39-19 •-• 687 



Means' for 1908 of eighteen Lighthouses on the 



Scottish coast 30'74 ... 6-68 



It is remarkable that the rainfall should be so small at 

 the Lighthouses, and that the law of rain-distribution 

 throughout the year should agree with that for the land- 

 stations. The smallest rainfall for 1908 was at the Isle 

 of May Lighthouse, where it was only 18-33 inches, with 

 C.G. at 690 ; and the heaviest rainfall was at Ardna- 

 murchan Lighthouse, where it was 50-99 inches, with C.G. 

 at 6-63. 



This method is readily applicable to the graphic presenta- 

 tion for a series of years either of the C.G. or of the 



NO. 2109, VOL. 83] 



rain-moment. Thus I have worked out the results for 

 Bangalore from 1867 to 1908, and find that while the 

 average position of the C.G. is 7-81, the positions for 

 1875 and 1876, the successive droughts of which caused the 

 0reat Mysore famine, were 6-82 and 672, and while the 

 average rain-moment is 276, it was for those years only 

 151 and 117 respectively. I also find that for the two 

 years 1907 and 1908 the C.G. for Bangalore was at 6-77 

 and 6-08 respectively, and that the rain-moments were 214 

 and 157 ; which agree with the fact that Mysore narrowly 

 escaped another serious famine quite recently, and give a 

 measure of the margin by which it escaped the disaster 

 caused by the rain deficiency of 1875 and 1876. 



It is evident that we might easily graph on the same 

 sheet for a sequence of years (i) the total rainfall ; (2) its 

 V early C.G. ; and (3) its rain-moment or coefficient. This 

 principle will also give the data for charts of the general 

 distribution of rainfall in a country for any year or series 

 of years. That each station and country has its rain- 

 constant which can be expressed numerically seems to 

 be more than a mei'e theoretical curiosity. 



f' J. Cook. 



30 Hermitage Gardens, Edinburgh. 



Lycopodium Spores. 



Miss Edith A. Stoney states (Nature, January 6, vol. 

 Ixxxii., p. 279) that with a large aperture microscope 

 objective and oblique illumination, Lycopodium spores are 

 seen to be coated with hair-like projections. We believe 

 this appearance to be illusory. Owing to the transparency 

 of the outermost layer of cells, the margin of the spore 

 is quite invisible under certain conditions, giving to the 

 radial cell walls the appearance of hair-like projections. 



Photomicrographs of some of these spores reproduced 

 in the Physikalische Zeitschrift of February i, p. 78, show 

 the effect in question in some parts of the field, and 

 evidence the correctness of the explanation given. 



John Zeleny. 

 L. W. McKeehan. 



Dr. H. J. Hansen and the Copenhagen Museum 

 of Zoology. 



I BEG permission to acknowledge the receipt of the open 

 letter sent me through your Journal of March 10, by the 

 leading zoologists of Great Britain and Ireland, regarding 

 my resignation from the Copenhagen Museum and my 

 zoological investigations. I am deeply conscious of the 

 great honour done me in sending me such an address, and 

 I regret that I am unable to write to all personally ; but 

 for that reason I would request them through your columns 

 to accept my most sincere and heartfelt thanks. 



H. J. Hansen. 



5te Juni Plads No. i, Kj6benhavn, F., March 17. 



Title of the Natural History Museum. 



What has history, in its present sense, to do with the 

 subject? What have the Muses to do with it? Certainly 

 Terpsichore is not included at any of the museums. The 

 N.H.M.(B.M.) is not a museum, but a Natureum. Might 

 not a ten-syllable name on the other side of the way be 

 replaced by the Arteum? Then Bloomsbury might use the 

 name Historeum. The address need not include London 

 or England, as no other place uses these terms. For all 

 scientific reference one word would be complete. 



W. M. F. P. 



The Meaning of lonisation. 



In his lecture at the Royal Institution on March 11, Dr. 

 Brereton Baker proposed the term electromerisation 

 instead of ionisation when applied to gases. May I venture 

 to suggest the word " electronisation " as more euphonious, 

 and as indicating the essential difference in the process, 

 viz. the freeing of electrons instead of ions? 



W. Deane Butcher. 



Holyrood, Ealing, March 18. 



