S6 



NATURE 



[Dec. 2, 1875 



Sachs's "Text-book of Botany," by Prof. E. R. Lankester, the 

 Savilian Professor is also spoken of as having " discovered the 

 sexuality of plants." It would interest students of the history 

 of botany to know to what extent the writer of either of these 

 articles is able to corroborate this statement by reference to ^ ir 

 Thomas Millington's writings. In his recently published " His- 

 tory of Botany," Prof. Sachs gives the following account of this 

 alleged discovery : — "In all histories relating to the subject of 

 sexuality, a certain Sir Thomas Millington — otherwise unknown 

 in the history of botany— is mentioned as deserving of the credit 

 of having first indicated the stamens as the male sexual organs. 

 The only information, however, which we have in support of this 

 is contained in the following statement by Grew in his 'Anatomy 

 of Plants,' 1682, p. 171, ch. 5, § 3 : — 'In conversation on this 

 subject' — viz., on the part played by the stamens (termed by 

 Grew the ' attire ') in the formation of seeds — ' with our 

 learned Savilian Professor, Sir Thomas Millington, he gave it 

 as his opinion that the ' attire ' serves as the male organ for the 

 production of the seed. I at once replied that I was of the 

 same opinion, gave him some reasons for it, and answered some 

 objections which might be made to it.'" * In the first edition of 

 Grew's work, 167 1, he attributes no sexual function to the 

 stamens; but in the edition of 1681 he thus continues, in sub- 

 stance : — It appears firstly, that the " attire " serves to separate 

 certain superfluous portions of the sap in order to prepare for the 

 production of the seed. Just as the foliature (floral leaves) 

 serves to carry away the volatile saline particles of sulphur, so 

 the " attire " serves to diminish and adjust the atmospheric por- 

 tions, in order that the seed may become more oily and its 

 principles better fixed. The flowers have therefore usually a 

 more powerful odour than the " attire," because the saline is 

 stronger than the atmospheric sulphur, which is too subtle to 

 aff"ect the senses. An analogy drawn from the animal kingdom 

 follows, which is hardly quotable ; but Sachs points out how 

 wonderfully any germ of truth in Grew's hypothesis was cor- 

 rupted by the chemical theories and strivings after a false analogy 

 of the day. It is difficult to see that there was really any 

 advance in this hypothesis upon the state of knowledge in the 

 time of Theophrastus (B.C. 371-286), who distinctly recognised 

 some individual plants as male, others as female. Whatever 

 merit also is due to Millington must, unless there is other record 

 of his services, be at least equally shared with Grew.+ It does 

 not appear, however, that either of these botanists even attempted 

 to confirm their conclusions by experiment. The merit of the 

 first discovery of the true function of the stamens is assigned by 

 Prof. Sachs to the German botanist Camerarius, in his " De 

 sexu plantarum epistola," published in 1694. This tract closes 

 with an ode, reminding one of Darwin's "Loves of the Plants," 

 beginning thus — 



" Novi canamus regna Cupidinis, 

 Novos amores, gaudia iion prius 

 Audita plantarum, latentes 

 Igniculos, Veneremque rairam." 



Alfred W. Bennett 

 6, Park Village East, London, Nov. 29 



The Late Eclipse 



On my return from India I should like to say a few words about 

 some letters which appeared in the English Mechanic during 

 my absence. Mr. Proctor, and a writer signing himself "A 

 Fellow of the Royal Astronomical Society," comment in these 

 letters on the result of the late Eclipse Expedition. It would be 

 better if these discussions were postponed until the results are 

 published by the Royal Society, but if writers who have not 

 heard anything beyond a few short telegrams take it upon them- 

 selves to enlighten the public as to the value of photographs 

 which they have not seen, a few remarks of one who has seen 

 them become necessary. 



If the telegrams written by me have given rise to the misun- 

 derstanding, I am sincerely soriy for it. I have had no personal 

 interest either in the success or the failure of the expedition. 

 The Royal Society has done me the honour to entrust me with 

 the task of carrying out a programme sanctioned in detail by the 

 Eclipse Committee. This I have done to the best of my ability, 

 and in wordmg the telegrams in question I avoided, carefully any 

 expression which might have raised expectations, not to be ful- 



* I liave not Grew's work at hand, and am therefore retranslating Sachs's 

 translation. 



\ Grew was bom in Coventry in 1628, and died in 1711 ; in 1677 he was 

 appointed Secretary to the Royal Society. 



filled on the arrival of the photographs. If the impression has 

 been propagated that the expedition his not obtained any results 

 of great importance, it is the fault of those who, thinking I had 

 an interest in exaggerating the importance of the results, have 

 taken away from the meaning of my words, which in reality 

 remained far below the truth. 



There cannot be the slightest doubt that the photographs 

 obtained by the prismatic camera are full of interest and im- 

 portance. They solve the question in which part of the spectrum 

 the chief photographic rays of the corona are situated. They 

 open out almost an entirely new field of inquiry, answering ques- 

 tions which could never have been answered by any other 

 method, and suggesting new questions to be answered hereafter. 



I should have liked to postpone the question whether it is 

 possible to photograph in all its details the spectrum of the corona 

 in the time available during eclipses, until Mr. Proctor's long- 

 promised mathematical solution has appeared. As, however, we 

 have had to wait for it already a considerable time, I venture to 

 submit to your readers the following considerations : — The pris- 

 matic camera is a spectroscope without collimator. It has given 

 us photographs after one minute's exposure, and would have done 

 so in less time under more favourable atmospheric conditions. If 

 we add a collimator and telescope to this camera, we shall have 

 an arrangement similar to that which actually was employed for 

 the photographs of the spectrum. If the lens of tl'.e telescope 

 is, as regards diameter and focal length, like that of the camera ; 

 if, further, the focal length and diameter of the collimator lens 

 is such tfiat it would collect all the light which passed through 

 the objective of the telescope, if the slit plate was removed, the 

 only di-ninution the intensity of the light would be caused 

 by the absorption through the two additional lenses and by the 

 diffraction of the slit. The influence of diffraction can be 

 reduced to a minimum by suitably altering the aperture of the 

 collimator lens and by using a slit not too narrow. We should 

 thus have an instrument capable of photographing the spectrum 

 of the corona in one minute. 



This is not the place to discuss whether the failure of the spec- 

 troscopic cameras was due to atmospheric causes, to the instru- 

 ments employed, or finally, to my own fault. It wUl, I believe, 

 be found hereafter, that the experience gained by even these 

 failures will prove useful on future occasions. 



In enumerating the results of the expedition the photographs 

 of the corona and the sketch taken by the Hon. H. N. Shore 

 ought not to be forgotten. The time observations were con- 

 ducted with as much accuracy as the instruments permitted. 



Sunnyside, Upper Avenue Arthur Schuster 



Road, N.W., Nov. 20 



Lommel's Optics 



I AM indebted to Prof. W. N. Hartley for a correction in my 

 review of Lommel's Optics, the proof-sheets of which did not 

 reach me in time for revision. The translator of the work is 

 evidently right in using the term napthalin red for the body 

 which exhibits the fluorescent spectrum depicted in Fig. 6 in the 

 article. The substance in question, Prof Hartley states, is also 

 called Magdala red, and has the elegant chemical name of 

 Azotrinaphthyldiamine. I am also obliged to my friend Prof. 

 H. M'Leod for pointing out that the mode of exhibiting the for- 

 mation of the rainbow described by Prof. Lommel, is to be 

 found in Jamin's " Cours de Physique" (tome 2, p. 782), 

 although the substitution of a spherical flask filled with water 

 for a solid glass globe, as described by Jamin, is more appro- 

 priate and convenient. Pouillet (tome 2, p. 769) also gives, I 

 see, a somewhat similar experiment, using a cylindrical glass 

 vessel filled with water. 



W. F. B. (" the Reviewer of Lomm.el's Optics") 



The Rainfall 



In Nature, vol. xiii., p. 70, under the head of "The Rain- 

 fall," you allude to the extraordinary rainfall for 1875 in Great 

 Britain, and call it a plague of rain ; you further call attention to 

 the astonishing fall of i 287 inches for each of the three hours 

 between 4 and 7 a.m. on the ist of September last, ar Sikawei, 

 in Cfiina ; and to the total quantity that fell there during the 

 twenty-four hours that elapsed between 4 p.m. on August 31 and 

 the same hour on the day following, viz. 8 "59 inches. 



I believe that a very heavy rainfall indeed was registered in 

 South Devon in September last, the fall in one hour and in a 

 total of twenty-four being unprecedented ; but I have mislaid 



