June 6, 1907] 



NATURE 



^35 



The source of the enormous deposits of sand is traced 

 partly to the sediment brought down by the Indus and 

 partlv to the drift from the littoral of Mirpur Sakro lying 

 to the south-oast of Karachi. While the control of the 

 waters of the Indus is primarily the work of the irrigation 

 department, it is urged that it would be possible to 

 reduce materially the sediment if the banks and certain 

 deposits, " kachas " in the upper waters were protected 

 bv planting with such grasses as Typlia elephantina, 

 Eragrostis cynosuroidcs, and Eleusine aegyptiaca. The 

 problem of checking the sand drift from Mirpur Sakro 

 is essentially one for the forester, and Mr. Betham main- 

 tains that, despite the want of water, it would be possible 

 to develop plantations of Casuarina, tamarisks, and 

 Agave. 



Dr. N. M. Stevens, in Publication No. 36 ol the 

 Carnegie Institute of Washington, has given an interest- 

 ing account of his investigations on the so-called hetero- 

 chromosomes in a number of insects, especially the beetles. 

 These chromosomes commonly form a pair differing in 

 size from the rest of these nuclear bodies. One of the 

 pair is smaller than the other, and this may go so far 

 as to culminate in its entire suppression. The special 

 point of interest attaching to these heterochromosomes 

 lies in their different behaviour in the male and female 

 animal respectively. The female always possesses an equal 

 pair, and in those forms in which the small one has 

 entirely disappeared from the cells of the male its 

 ■surviving counterpart is still preserved in the female. A 

 comparison of the eggs and sperms brings out the remark- 

 able fact that half the eggs contain, and half quite lack, 

 the large chromosome, whilst similarly the sperms, four 

 of which are produced from each mother cell, divide the 

 big and little ones between them when both are present, or 

 they lack them altogether when they are absent from the 

 somatic cells of the species. Thus it comes about that on 

 fertilisation, on the average, half the offspring possesses, 

 and half are destitute of, the large chromosome. Stevens 

 correlates these remarkable nuclear characters with the 

 differentiation of sex, but exercises a judicious restraint in 

 forcing his conclusions. The paper contains full details, 

 and should be consulted by those interested in these 

 matters. 



At the annual meeting of the American Antiquarian 

 Society on October 24, i<)o6. Dr. A. Lawrence Rotch read 

 a paper entitled " Did Benjamin Franklin Fly his Elec- 

 trical Kite before he Invented the Lightning Rod?" It 

 is generally supposed that the kite experiment led to the 

 invention of the rod, but Dr. Rotch's researches seem to 

 show that the experiment was probably performed later 

 than has been supposed (June, 1752), and that before then 

 certain buildings in Philadelphia were provided with 

 "points," probably as lightning conductors, and, further, 

 that prior to Franklin's first account of the kite experi- 

 ment he had drawn up precise directions for the erection 

 of lightning rods. These directions were printed in " Poor 

 Richard's (Improved) Almanac " for 1753, which was 

 advertised in the Pennsylvania Gazette of October 19, 

 1752, as being then in the press. It is admitted that 

 Franklin suggested the possibility of the lightning rod as 

 early as 1750, but the directions referred to by Dr. Rotch 

 and reprinted in his paper show that it was probably in- 

 vented about a year earlier than has been supposed. 



The twenty-ninth report of the work of the Deutsche 

 Seewarte, Hamburg, for the year 1906, shows that, in 

 common with other national meteorological organisations, 

 NO. 1962. VOL. 76] 



the scope of its operations is constantly increasing, with 

 the result that some important investigations necessarily 

 fall into arrear, e.g. the publication of the valuable " Daily 

 Synoptic Weather Charts for the North .Atlantic Ocean," 

 undertalven in conjunction with the Danish Meteorological 

 Office, which had commenced its twentieth year at the 

 time of the issue of the Hamburg report for 1906. With 

 regard to the necessary collection of trustworthy observ- 

 ations at sea, we observe that the Deutsche Seewarte re- 

 ceived in 1906 some 1592 logs of different kinds from 

 Imperial and mercantile vessels, containing 3627 months' 

 observations. The observers are encouraged by the award 

 of medals and diplomas, as well as by liberal presentation 

 of publications. The department dealing with agricultural 

 meteorology has greatly enlarged the area of its work, 

 and issues special weather forecasts and charts in connec- 

 tion with that service. The important investigation 'of 

 the upper air by means of kites and balloons is continued 

 whenever practicable; 206 kite ascents were made in the 

 year. 



In the Geological Magazine for April, Mr. G. J. Williams 

 discusses the geological age of the Parys Mountain, 

 Anglesey, and records a number of fossils recently dis- 

 covered in shale beds opened up by the boring of a tunnel 

 in the Mona Mine. 



Prof. Charlotte A. Scott contributes to the .innals of 

 Mathematics, viii., 3, an interesting note showing how the 

 regular polygons of five, seven, or nine sides can be con- 

 structed by determining four of their vertices as the points 

 of intersection of a circle and a rectangular hyperbola. 



In the Journal de Physique for May, M. Ch. Maurain 

 discusses the influence of torsion on magnetisation, and 

 refers to the methods adopted in order to separate the 

 effects of torsion from those of hysteresis. This paper may 

 with advantage be taken in conjunction with one by 

 K. Honda and T. Terada on the change of elastic con- 

 stants of ferromagnetics, published in the Journal of the 

 College of Science CTokyo), vol. xxi., art. 4. 



.\n interesting paper on the genesis of mathematics is 

 contributed by M. Jules Sageret to the Revue scientifique 

 (vii., 19). The author gives a detailed account of Rouse 

 Ball's observations on the Rhind papyrus, and refers to 

 Tannery's conclusions regarding the work of the geo- 

 metrical schools of Thales and Pythagoras. He considers 

 that mathematics originated out of an empiricism which 

 might have attained a high stage of development before 

 any science came into existence, and that the fertile germ 

 came from certain metaphysical ideas of imagination 

 (shall we say intuition?) in the early ages of human 

 thought. The genesis of mathematics differed from that 

 of other sciences owing to the important part played in 

 the latter by experience and observation. We can only 

 wish that papers on the lines of M. Sageret 's appeared 

 more frequently in popular journals in Britain. They 

 would do much to remove that unpopularity of mathe- 

 matical study which arises from a too exclusive consider- 

 ation of the mere examination ideal. 



In the Psychological Bulletin (iv., 4), Mr. David Coyle 

 contributes a note on the 'nversion of the image in vision, 

 and points out that the eye-movement theory of upright 

 vision does not necessitate the inversion of the retinal 

 images. In other words, an organism fitted with an eye 

 capable of giving an upright image would execute the same 

 eye-movements in turning its eye towards any definite 

 object. In connection with this simple result, it might 

 be interesting to direct attention also to the ease with 



