Ianuary i 6, 19 19] 



\AIURE 



393 



..-■—necessary to make the relations between man 

 and Anopheles sufficiently intimate and continuous 

 to bring about endemic malaria are in France found 

 only exceptionally where man has retained or re- 

 sumed a primitive mode of lift-. M. Roubaud con- 

 cludes that human progress has brought about a 

 suspension of the previously intimate relations be 

 man and Anopheles, and, consequently, the disae 

 ance of the old foci of malaria. 



"A Win 111 H \i 1 1 Botanical Garden" is the subject 

 of an in teres tin j Mr. \V. Roberts in the 



Gardi ,.1 December 21, 1918. The 



writer has acquired a sale catalogue of a "Collection 

 of plants, shrubs, and fruit-trees; consisting chiefl) 

 ol valuabl leautiful flowers, and a lar^e 



number of pines in full fruit and succession; of Mr. 

 William Bennett, corn factor and biscuit baker, 

 deceased," to be sold on March -'7, 17011, at the 

 11 in Whitechapel Fields. Nothing further is 

 m of William Bennett, but the catalogue indi- 

 ■ that the garden was of a very special and 

 interesting .nature, and the approximately accurate 

 botanical character of the nomenclature proves that 

 Bennett's interest was as much botanical as horticul- 

 tural. His garden contained several specimens of 

 many plants which were rare in this countrv a cen- 

 tury and a half ago, Many of the plants in the list 

 were of comparatively recent introduction, and several 

 appear to have been grown by Bennett many years 

 earlier than the dates recorded for their introduction 

 into Great Britain; Mr. Roberts instances Selago spuria, 

 Pisonia aculeata, and Ruellia ciliata. The exotics are 

 from widely different regions, tropical and otherwise. 

 According to a contemporary map, Whitechapel Fields 

 occupied a broad space on the south side of White- 

 chapel Road and Mil'- End, extending east from the 

 present-day London Hospital down nearly to Ratcliff 

 hway. Adjoining them were the Mulberry 

 Gardens. 



The recently published issue of the Imperial 



Institute Bulletin (No. -•. imiS) contains -useful articles 



South African grasses for paper-making, Ceylon 



tobacco, and cotton in Egypt. Of the South African 



[ndropogon hirtiflorus is said to be quite 



suitable for the manufacture of paper pulp on a com- 



ial scale, but the other grasses appear to be of 



value mainly in South Africa. Tobacco in Ceylon 



has been taken up with the view of obtaining an im- 



1 type of pipe tobacco, and judging from the 



report, the trials appear to have met with success. 



With regard to cotton, Mr. G. C. Dudgeon, consulting 



ilturist to the Ministry of Agriculture, Egypt, 



discu the question of the maintenance of the 



qualitv of Egyptian cotton, ft is well known that 

 if any serious deterioration in the quality of Egyptian 

 cotton occurred, it would inflict great damage on the 

 fine cotton spinning industry. Mr. Dudgeon 

 points out that Egyptian cotton has in recent years 

 consisted of a number of varieties of cotton, each an 

 improvement on its predecessor, and each in its turn 

 • d to deterioration through crossing in the 

 with inferior kinds. The quality of the cotton 

 produced has, however, on the whole improved, but 

 unle«- rtem of protecting improved kinds is 



introduced there can be no guarantee that the present 

 quality of the output can be maintained. The 

 principal action required is the isolation and issue of 

 the best kinds in a fairlv pure state, and the 

 steps necessary to this end can be taken by Govern- 

 ment only with the consent and active support of 

 th>» Egyptian producers. 



XO. 2568, VOL. I02] 



The Bureau of Standards of the United States has 

 issued an emergency edition of its Circular No. 27 on 

 the properties and testing of optical instruments, 

 pending a more complete revision of the circular in 

 a few months. It contains a large amount of informa- 

 tion on the design and the principal causes of imper- 

 fections of optical instruments not easily accessible to 

 the general public owing to its being scattered widely 

 in optical text-books and periodicals, 'and to the mathe- 

 matical form in which it usually appears. The cir- 

 cular deals in succession with definition and resolving 

 power, magnification, brightness of image, and field 

 of view of instruments of observation, with the 

 is aberrations and distortions of instruments for 

 reproduction, and with instruments for measurement. 

 Many of the simpler tests for such instruments are 

 di -.libed, so that it is quite possible for the owner 

 of an instrument to test it himself, but in case more 

 complete tests are required the Bureau undertakes 

 thj n at fees from a dollar upwards. No charge is 

 made for tests undertaken in the public service or in 

 aid of researches for the development of the optical 

 instrument industries of the United States. 



In the September issue of the Science Reports of 

 the University of Sendai Prof. K. Honda and Mr. 

 J. Okubo give a new theory of magnetism which 

 agrees more closely with the observed facts of para- 

 and diamagnetism than any previous theory. Ac- 

 cording to it, the molecular magnets rotate about 

 axes not in general coincident with their magnetic axes. 

 The component of the magnetic moment of a molecule 

 along the axis of rotation the authors call the axial, 

 and that at right angles the transverse, component. 

 When a magnetic field acts on ths molecule, preces- 

 sion and nutation take place owing to the axial com- 

 ponent of the magnetic moment. The nutation is 

 damped out by thermal impacts amongst the mole- 

 cules, but the precession continues at an angle which 

 implies increase of magnetic moment in the direction 

 of the field, and the effect is paramagnetic. The 

 transverse component of the moment causes the rota- 

 tion of the molecule to be faster when that component 

 is in the same direction as the field, and to be slower 

 when in the opposite direction. The time mean of the 

 effect is therefore in the opposite direction to the field 

 —that is, it is diamagnetic. The preponderance of 

 one effect over the other determines the para- or dia- 

 magnetic character of the material. 



Baume's hydrometers, especially the one for liquids 

 heavier than water, are largely used in various indus- 

 tries. As is well known, much confusion has arisen 

 in the conversion of the hydrometer readings into 

 terms of specific gravity. This is due to the fact that 

 in graduating the early instruments the temperature 

 of the water used was not given precisely, nor was 

 the density of the "heavier" liquid (a solution of salt) 

 correctly obtained. Hence several different conversion 

 tables have been employed, showing, of course, 

 different specific gravities for the same hydrometer 

 reading. The formula for conversion is : Degrees 

 Baume = m — m "sp. grav., where m is the constant or 

 modulus on which the scale is based, and the uncer- 

 tainty has been as to the true value of m. The Bureau 

 of Standards, Washington, holds that the value should 

 be 145, and this is now adopted generallv in the United 

 States except in the sugar industrv. A new conversion 

 table has recently been issued by the Bureau, based 

 on the value mentioned and on the spa li ter- 



minations of F. Plato, which are regarded as the most 

 The temperature adopted is 20 C. These 

 features, it is considered, should especially commend 



