Aug. 6, 1874] 



NA TURE 



263 



So far is it from being true that I have represented hovering 

 as an accomplishment of wingniansliip wliich requires little exer- 

 tion, that I have asserted with emphasis the exactly opposite 

 doctrine — that it is a specially difficult operation, requiring very 

 often great exertion, and always requiring special muscular 

 cflfort. 



It is evident, however, that Mr. Guthrie is still ignorant of 

 the facts which have to be explained. In the passage which he 

 misquotes I am not stating any theory ; I am stating a fact 

 which I have seen over and over again. It is a fact beyond all 

 question that a kestrel can maintain itself hovering in a strong 

 horizontal air-current, with no other muscular exertion than that 

 which is required to keep its wings and body at th riglit angle. 

 I have seen it done a hundred times in level countries, when by 

 no possibility could any upward deflection of the wind have 

 arisen from the configuration of tlie ground. 



One of the first and most fundamental facts to be admitted 

 and accounted for in the flight of birds is, that perfectly hori- 

 zontal air-currents have a powerfully sustaining effect upon vane 

 surfaces, which are presented to them as birds' wings are pre- 

 sented. " Hovering" and "soaring" are only to be explained 

 when this fact is seen and admitted. ■ Argyll 



Inveraiy, Argyllshire, July 30 



Exhibition of Specimens and Apparatus at British 

 Association Meetings 



I AM anxious to draw the attention of the readers of Nature 

 to the arr.angf nients to be made this year at the British Associa- 

 tion meeting (for the first time) for the reception of specimens 

 and apparatus illustrating papers or short communications made 

 to the sections. The provisioir of a room for this purpose — a 

 kind of temporary museum — has during the last four years been 

 recommended by the committees of Sections C and D, several 

 times, and this year the experiment is to be made. Those who 

 have promoted this plan are naturally anxious that it should be 

 a success. I would therefore appeal to the secretaiies of the 

 various sections to assist in initiating this new feature of the 

 meeting, by endeavouring, as far as possible, to secure from the 

 authors of papers objects which illustrate their communications ; 

 such objects to be deposited during the week of meeting in the 

 room provided by the Council. This room will be open to 

 inspection under the same regulations as the sectional meeting 

 rooms, and the objects deposited will be carefully ticketed and 

 arranged, and, where necessary, placed under glass cases. 



From Section A we may expect physical and astronomical 

 apparatus and models ; from 15, new chemical products and 

 specimens of apparatus illustrating new processes ; from C, 

 geological specimens of rarity or new to science ; from D, 

 zoological and botanical specimens, anatomical preparations, for 

 the exhibition of which microscopes will be provided, and 

 also ethnological specimens ; from E, maps and geographical 

 models ; from F and G, models or machinery not too large for 

 a room. 



It is necessary to mention that objects exhibited must be in 

 illustration of some communication (however short) to one of 

 the sections, in order that they may thus be sanctioned by the 

 committee of such section. 



By the co-operation of the sectional secretaries with the mem- 

 bers of the committee appointed to superintend the arrange- 

 ments of this room or repository, we ought to succeed in addnig 

 an important and valuable feature to the scientific interest of 

 the meetings of the Association. E. Ray Lamcesier 



A Waterspout at Milford Haven 



The enclosed account of a waterspout which was sent to me 

 by one of our telegraphic reporteis may perhaps be of interest 

 to your readers. RoiBERT II. ScOTX 



Aug. I 



"St. Ann's Head, Milford Haven, July 28 



" Sir, — The w.aterspout mentioned in this morning's report 

 was observed yesterday at 4.50 r.M., about a mile outside the 

 port, following in the wake of a squall. Its course lay about 

 N.E., and the progressive movement was judged to be between 

 twenty-five and thirty knots per hour. Its diameter at the base 

 was about 40 ft., and the direction of the whirl from left to right, 

 or with the hands of a watch. The lower portion was well 

 defined, but the middle and upper portions were not so distinct ; 



in fact, the connection with the clouds above, although un- 

 doubtedly existing, could not be discerned from our point of 

 view-. The sea immediately under it was greatly agitated and 

 white with foam, the spr.ay ascending in a spiral form. 

 Thunder was heard with tlie squall that jireceded it, and the 

 wind veered from S. to S.S.W., although it backed to S. again 

 afterwards. (Signed) John C. W.\lker 



"R. H. Scott, Esq." 



Periodicity of Rainfall 



My attention has been recalled to the letter (vol. viii. p. 547) ol 

 my old friend Mr. Meldrum, dated Sept. 15 last, upon the above 

 subject, by its recent republication in a Barbados newspaper. I 

 had intended at the time to examine whether his objections to 

 my statements were valid, but absence from the island and other 

 occupations interfered. On reperusing his letter, I perceive that 

 he notices a disagreement between my figures and those given by 

 Mr. .Symons, which requires to be explained, and I take the 

 opportunity of endeavouring to remove his doubts with regard 

 to the correctness of my results. Mr. .Symons's annual averages 

 for 1S43-61 were drawn from one station, or rather from two; 

 from Fairfield for the years 1S43-46, .and from Halton, a station 

 nearly three miles distant, and having twice the elevation, for 

 the rest of the period. My averages were taken for the first four 

 years from the same single station, the only record then in exist- 

 ence, and from a varying number of stations during the other 

 years. 



Mr. Meldrum thinks that, with certain alterations which he 

 suggests, my calculations will support his theory. I should be 

 very glad if they did. My object in pursuing my inquiries into 

 the rainfall of Barbados has been to assist the planters in fore- 

 casting the coming seasons, so as to guide them in their agricul- 

 tural operations; and I would gladly welcome every contribution 

 to this end, whether it be Mr. Meldruni's sun-spots or Prof. 

 Chase's lunar influences. I was therefore disappointed when I 

 found that the experience of this island did not coincide with 

 that of Mauritius, and I am sorry that a further comparison of 

 the data, which is not open to any objection of discordance of 

 elements, confirms my first calculations. 



If I take Fairfield and Halton alone, for the thirty-one years 

 1S43 73, I obtain the following results : — 



1843-45 

 1847-49 



1855-57 

 1S59-61 

 I 866-68 

 1870-72 



158-3 



i57'i 



1637 



177-8 



Total 



502 'O 5I2'2 



This calculation shows an annual average excess in iniiiimum 

 years of 3 '4 inches. But the rainfall at Fairfield during the last 

 three years, for which alone I have the means of comparison, is 

 '3'33 per cent, below that of Halton. Therefore 21 '7 inches have 

 to be added to the minimum average of 1843-45, which would 

 increase the above excess to io'6 inches. 11 Halton alone be 

 taken for the five periods, the average of the maxima is l67'3, 

 and that of the minima 174' 2, yielding an excess of minima of 

 69 inches. 



A comparison of three stations for 19 years, 1855-73, being 

 the longest comparable period, exhibits the same results. These 

 three stations, Halton, Binfield, and Husbands, are situated in 

 opposite parts of the island, and furnish a fair average of the 

 whole : — 



M.aximimi years. Minimum yci.s. 

 1927 



Total ... 356-3 375'3 



This calculation shows an annual average excess of 9-5 inches 

 in iiiiiiiiiuini years, which dilTers only by I'l inch from the 

 above corrected calculations founded on the returns of a single 

 station. 



Mr. Meldrum, in his letter of September, writes, that I have 

 " taken 1846 and 1871 as middle maxima years [in my first paper 

 I also took 184S], whereas 1849-72 are probably more cor- 

 rect." Mr. Meldrum is in error as to my having taken 1846 as 



