September 3, 1903] 



NATURE 



415 



lively Jerusalem, Purgatory, the Ganges, and Morocco. 

 Dante imagined that, with respect to Jerusalem, 

 the Ganges was the extreme east and Morocco 

 the extreme west. The four important divisions of 

 the day, mezzodi or midday, sera or evening, 

 mczzan'otte or midnight, and m'attino or morning, are 

 represented by lines towards the circumference. At 

 ihi beginning of the poem Gerusalemme must be 

 jjlaced at the top of the circle, with Mattino over it. 

 Now looking southwards, holding the dial straight 

 before us, it will be found that the sun on the dial 

 follows the same course as the real sun. The lines in 

 the Inferno, Purgatorio, and Paradiso which contain 

 he time allusions are given in Italian and in Long- 



llow's English translation, and the author finds that 

 ihe whole duration from the beginning of the poem 

 to the final morning in Purgatorio is seven and a half 

 days, i.e. seven days from the entrance with Vergil 

 into Hell. 



The conceptions of great poets like Dante and 

 Milton must ever be of interest, though we Cannot, of 

 course, expect them to be in agreement with modern 

 astronomy. The latter, though constructing the 

 universe according to Ptolemy, yet. Hying after 

 C'opernicus, and being personally acquainted with 

 (ialileo, evidently had misgivings with regard to the 

 truth of that svstem. None such troubled the mind of 

 Dante; to him' the earth was the centre of the universe, 

 both in appearance and in reality. But M. Pradeau 

 presents a scheme concerning his views as bearing 

 upon the progress of time in the " Divina Commedia " 

 which is both ingenious and consistent with itself. 



W. T. L. 



1 School Geometrv. Part iii. By H. S. Hall, M.A., 

 and F. H. Stevens, M.A. Pp. vii+137 to 210. 

 (London : Macmillan and Co., Ltd., 1903.) Price 15. 



In this volume we have a further instalment of the 

 new text-book of elementary geometry which the 

 authors have in preparation, a school geometry based 

 un the recommendations of the Mathematical Associ- 

 ation and the recently adopted report of the Cambridge 

 Svndicate. 



"The present contribution deals with the geometry 

 of the circle, and contains the substance of Euclid, 

 book iii., 1-34, and a portion of book iv. The authors 

 have omitted sotne of Euclid's propositions, and have 

 not adhered strictly to Euclid's sequence, but the 

 Euclidean form of proof has been retained. 



The conception of a " limit " is appropriately intro- 

 duced in explaining the nature of tangency, and in 

 establishing some of the propositions. 



The exercises, which follow the propositions at short 

 intervals, are partly deductive and partly graphical, 

 the latter requiring the use of compasses and scale, 

 the numerical answers being collected at the end of 

 tlie volume. The exainples are simple and well 

 graduated. 



We consider that problem 23 would be better omitted, 

 together with the exercises based thereon. It is of 

 no practical value, and should be consigned to the 

 Euclidean relics. Every draughtsman knows that a 

 line can be drawn with greater accuracy to touch two 

 given circles than to pass through two given points, 

 and if the points of contact are wanted, they can be 

 determined subsequently by drawing perpendiculars 

 from the centres of the circles. 



The circumference and area of a circle are briefly 

 dealt with on p. 198. The experimental determin- 

 ation and verification of these quantities might with 

 advantage have been more fully gone into. The book 

 concludes with some propositions on circles and 

 triangles, including a demonstration of the property 

 of the nine-points circle. 



NO. 1766, VOL. 68] 



LETTERS TO THE EDITOR. 



[ The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond uitth the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



American Botanic Laboratory in Jamaica. 



The Director of Kew presents his compliments to the 

 Editor of Nature and requests the fa%'our of his publishing 

 the enclosed letter. 



Kew, August 23. 



Sir William Thiselton-Dyer, 



Royal Botanic Gardens, 

 Kew, 



Surrey, England. 

 My dear Sir, 



The Government of Jamaica has decided to relinquish 

 its use of the buildings at Cinchona. The experimental 

 and botanical plantations are, however, to be maintained 

 as before. The Surveyor-General of Jamaica offered under 

 public advertisement on June 15 the group of buildings 

 known as Beilevue and some land for rental. I have 

 personally accepted this rental for the purpose of saving the 

 station for scientific purposes, and with the plan of establish- 

 ing there, if possible, the long desired botanical laboratory 

 in the American tropics. At my request. Dr. MacDougal 

 has recently visited Jamaica to arrange details of the lease, 

 and .reports that the buildings and their furnishings are 

 already comfortable and well adapted for the use of 

 investigators. 



Dr. MacDougal and I . decided _to take these steps after 

 consultation and correspOrtdence with Prof. Underwood, 

 who spent the early part of the year in Jamaica in the 

 study of ferns, and who is now in Europe ; with Dr. Duncan 

 S. Johnson, who has recently returned from Jamaica, where 

 he has been collecting material for embryological studies ; 

 with Mr. Wm. R. Maxon, who was with Prof. Underwood 

 there during the spring ; and with Prof. Earle, who spent 

 last November in Jamaica in mycological investigations. 

 Dr. MacDougal was already familiar with the locality 

 from his visit there with I'rof. Campbell in 1897, and we 

 had discussed the topic with the Hon. Wm. Fawcett, 

 director of the public gardens and plantations of Jamaica, 

 while he was in New York last autumn during the meeting 

 of the Plant Breeding Conference. The aid and cooperation 

 of all who regard the securing of Cinchona as a proper and 

 desirable act will be needed to maintain such a laboratory, 

 and to this end I ask that you write me your opinions on 

 this subject, and to indicate what aid you can render, and 

 whether either you or your students would wish to make 

 use of the station during the next year, and if so, for what 

 length of time approximately. 



I may say that the Jamaican Government is heartily in 

 sympathy with the enterprise, and will cooperate to a very 

 important extent, furnishing facilities for growing plants 

 under the widely different climatic conditions offered bv the 

 gardens at Cinchona, Hope, and Castleton, the use of the 

 large botanical laboratory and herbarium at Hope, and the 

 use of visitors' tables in the laboratory at Hope. 



As regards Cinchona, I quote the' following from Prof. 

 Underwood's account of his work in Jamaica from the July 

 issue of the Journal of the New York Botanical Garden : — ' 



" Not the least important of the results of the expedition 

 was a possible solution of the problem of a suitable location 

 for a tropical laboratory, which has long been under con- 

 sideration by American botanists. At the time of the visit 

 of the committee appointed some years ago to investigate 

 the subject, the plant at Cinchona was occupied by the 

 Government botanist, and was consequently out of the 

 question. A one-story six-room house, three or four low 

 buildings suitable for laboratory work, with two green- 

 houses of sufficient capacity to conduct experimental work 

 under glass, could be had of the Jamaica Government at 

 a nominal rent. Cinchona is nearly a mile above the sea, 

 with a delightful climate (the extremes of temperature for 

 the past twenty years being 45° F. and 70° F.), a delightful 

 outlook, and as closely accessible to virgin forest as could 

 be obtained. Within three miles, nearlv on a level, is 



