August 4, 19 10] 



NATURE 



greater part of the volume, which exceeds 200 pages, is 

 taken up by the enutneration of genera and species with 

 references to the various papers where they are mentioned. 

 The compiler. Dr. \V. J. Jongmans, of Leyden, makes an 

 appeal for assistance in the shape of literature and papers 

 as published. 



The systematic position of the tropical American genus 

 Phytelephas, well known because the stone-like endosperm 

 furnishes a cheap substitute for ivory, is discussed by Mr. 

 O. F. Cook in vol. xiii., part v., of " Contributions from 

 the United Stales National Herbarium." The author traces 

 an affinity with .Manicaria, a Central American genus, in 

 the number of stamens and the fruit, besides noting an 

 agreement with .Attalea in the germination of the seedling. 

 This leads to the formation of a family, Manicariacese, 

 connecting the PhytelephantacecE with the Cocaceae. At 

 the same time, the author controverts a family relationship 

 between Nipa and Phytelephas. 



Prof. H. Moliscii communicates to the Silziiiigsbericbtc 

 der Kaiserlichcn Akademie der Wisseiischaftcii, Vienna 

 (vol. cxviii., part ix.), a note on local coloration of the 

 cell wall in certain water plants induced by manganese 

 compounds. Tlie introduction of manganese salts into 

 cultures of Elodea produces, after a few days' exposure to 

 light, a deposition of brown matter in the outer walls of 

 the epidermis which on continued exposure tends to mask 

 the green pigment in the leaf. The author notes that the 

 deposition takes place only when the plant is exposed to 

 light, and that a similar result was obtained in leaves of 

 Vallisneria, Ranunculus aquatilis, and Myriophyllum. The 

 thief point of interest lies in the fact that it furnishes a 

 definite instance of localised action produced by the absorp- 

 tion of a specific element. 



During the coming December an exhibition is to be held 

 at .•\llahabad, at which a special feature will be the dis- 

 play of small light machinery for use in agriculture and 

 the allied industries. A pamphlet entitled " Northern 

 India as a Market for Agricultural Machinery " has been 

 issued, not only with the purpose of interesting manu- 

 facturers in the exhibition, but to give useful information 

 to those who have in the past found it difficult to ascertain 

 the special requirements of the vast Indian market. It 

 should serve its purpose admirably. 



The fertilising value of seaweed has for some time past 

 been the subject of a long arbitration case in Scotland. 

 From the reports that have appeared in the North British 

 Agriculturist, it seems that three farmers were deprived 

 of their rights to gather seaweed when the Admiralty 

 resumed possession of the foreshore at Rosyth for the pur- 

 poses of naval construction. The facts were not contested, 

 and the only dispute was as to the value of the seaweed. 

 Experts and practical men were called on both sides, and 

 the values assigned varied from is. per ton to qs. 3Jd. ; 

 in the end the arbitrator fixed 4^. gd. and awarded com- 

 pensation on this basis. As the case has been going on 

 for eight months a considerable amount of money must 

 have been spent, while it cannot be said that any material 

 addition to our knowledge of the subject has been gained 

 in consequence. The pKerblem could only be solved by 

 experiment, and it is reverting to the methods of the 

 medircval schoolmen to attempt to settle it by collecting 

 " opinions." 



The tobacco produced in India has not hitherto been 

 held in high repute, nor has success been attained by the 

 introduction of .American varieties and methods of curing. 

 NO. 212;, VOL. 84] 



Mr. and Mrs. Howard have for some time been engaged 

 in a study of the varieties already grown in the country, 

 and have published their results in vol. iii. of the Memoirs 

 of the Department of .Agriculture in India. Perhaps no 

 other factor in the production of high-grade tobacco is so 

 important as uniformity in the crop, both as regards 

 growth and also as regards the type of plant grown . 

 Unless the crop ripens evenly the difficulties of harvesting 

 and curing are increased, whilst a crop made up of several 

 types of plant is not readily sorted out into uniform grades. 

 The various types of Nicotiana ruslica and N. tabactnn 

 are described in sufficient detail, and typical photographs 

 are given. A great deal of patient work of this kind is 

 necessary before the breeding of new varieties can usefully 

 be begun. 



Prof. A. L. Rotch has coniributed to the epitome of 



the Aeronautical Annual, 1910, a useful article on the 



relation of the wind to aerial navigation, .\fter explaining 



the methods of investigating the upper air employed at 



Blue Hill Observatory and elsewhere by means of kites 



and sounding-balloons, he refers to the results of the upper 



wind observations in the eastern United States and to the 



recent discussion of the data by Mr. A. H. Palmer. The 



surface wind at Blue Hill (200 metres) has a mean annual 



velocity of 7-1 metres per second (15-8 miles per hour), 



and increases with height, as follows ; — 



Height in metres 551 icxw 2505 3500 5400 6400 



Mean velocity, m.p. 5. g'S 10-7 12-5 15-5 24-9 27-1 



and the increase continues to the greatest heights; at 

 <)5oo m. ft is 358 m.p.s. (So-8 miles per hour). The mean 

 range from summer to winter increases very greatly with 

 height : — 



Height in metres 200 — 1000 1000 — 3000 3000 — ^oco 5000 — 7000 

 Velocity in summer 7*5 8"2 io'6 iq'i 



Velocity in winter 8"S 14*7 21*6 49"3 



the velocity of the upper winds in winter being more than 

 double the rate in summer. The velocity increases nearly 

 twice as fast at night as in the daytime up to about 

 500 m. ; above that height there is a decrease, except in- 

 winter, up to 1000 m., and then a steady increase. The 

 author points out that at night a suitable level for aeria^ 

 navigation in summer is 1000 m. ; in the daytime it is 

 necessary to ascend above the cumulus clouds. Over the 

 temperate regions the surface winds are obviously con- 

 stantly changing their direction ; above these shifting 

 winds, the balloons sent off from St. Louis showed that 

 the direction is generally westerly. Above the height of a 

 mile the mean direction was from west-north-west. 



The results of a series of investigations by Messrs. 

 de Broglie and L. Brizard, on the ionisation of gases in 

 presence of chemical reactions, are summarised by the 

 authors in the June number of Le Radium. Of the three 

 methods adopted by the authors, that in which the ultra- 

 microscope is used has proved the most powerful. The 

 chemical reaction to be investigated is carried out under 

 the microscope and between two charged plates which pro- 

 duce an electrical field across the line of vision. Any 

 charged particles produced by the reaction are moved 

 towards one or the other plate, according to the sign of 

 the charge. A large number of reactions have been 

 observed in this way, and the authors conclude that in 

 none is the ionisation, if produced, due primarily to the 

 chemical reaction, but to secondary effects, such as the- 

 bubbling of a gas through a surface of separation of two 

 fluids, or the breaking down of crystalline structure and 

 the projection of particles which become charged by friction 

 with the surrounding medium, or, lastly, to the in- 

 candescence produced by the heat of reaction. It will be 



