March 15, 1894] 



NA TURE 



461 



no break nor change of slope for the intervals during which the 

 current was passing. Thus it wouM appear that the current 

 does not sensibly affect the diffusion of copper sulphate and sul- 

 phuric acid through a gold-leaf partition. In the experiments 

 oil the "critical current " it was found that the concentration of 

 the electrolyte exerted an important influence on the value 

 obtained, and the measurements made indicate that the "critical 

 current" is proportinal to the conductivity of the electrolyte. 

 Experiments made to determine whether the variation of the 

 temperature has the same effect upon the "critical current" as 

 upon the conductivity, are not yet sufficiently complete to justify 

 conclusions being drawn. 



Mr. Henry Gannett, of the United States Geological 

 Survey, has published the results of his calculation of the 

 average elevation of the United States with a magnificently- 

 coloured contour-map of the whole area on the scale of about 

 100 miles to an inch. The contouring is in large part hypo- 

 thetical, but the discussion takes all considerations into account 

 in order to present the results as accurately as possible. It is 

 estimated that the mean elevation of the United States is 2500 

 feet, a little grea'er than Dr. Murray's estimate of the mean 

 elevation of the land of the globe. Delaware is the lowest 

 State, averaging only 60 feet above sea-level, while Wyoming 

 and Colorado are the highest, respectively 6700 and 6800 feet. 

 Eleven States are above the average level, all being on the 

 Pacific coast or in the adjacent Cordillera region. Florida and 

 Louisiana are the least elevated States next to Delaware, being 

 only 100 feet in average height. In making these calculations the 

 levels of railway lines were extensively utilised to supplement the 

 somewhat scanty determinations of altitude made by official 

 surveyors. 



The few regions of Europe still unexplored formed the subject 

 of consideration at the last meeting of the Royal Geographical 

 Society, when Mr. W. H.Cozens-Hardy described his recent jour- 

 ney through Montenegro and the borders of the adjacent Turkish 

 provinces of Albania and Novi-Bazar. Mr. Cozens-Hardy has 

 been able for the first time to map accurately the frontiers of 

 Montenegro ■. fined by the Treaty of Berlin, and he succeeded 

 in gaining the good-svill of the people, penetrating for some dis- 

 tance into Albania, where the practically independent tribes still 

 make travelling dangerous. The northern and eastern parts of 

 Montenegro consist of grassy mountains, forests, and fertile 

 valleys, contrasting with the bare rocky hills and river-basins of 

 the coast region and the centre. 



Three Norwegian whalers have attempted seal fishery in the 

 Antarctic waters south of the Falkland Islands during the 

 southern summer now ending. One of these vessels was as far 

 south as 69" or 70 without finding enough ice to make sealing 

 profitable, and it is reported that a considerable extent of new 

 land has been discovered and charted. 



The botanical collections made by Messrs. Burk and W. E. 

 Meehan during the Peary expedition, are described in the 

 Proceedings of the Philadelphia Academy, under the title 

 "Contribution to the Flora of Greenland." One hundred 

 species of flowering plants and vascular cryptogams are enume- 

 rated, thirty-nine of lichens, and twenty-eight of mosses. 



Herr S. Csapodi records in the Silziingsberichte of the Un- 

 garische natur-aiissenschaftliche Gesellschajt zwii Budapest, the 

 curious fact that several mould-fungi, especially Aliicor Mucedo, 

 will grow on solid compounds of arsenic, giving off arsenical 

 vapours. This may be compared with Zukal's observation of 

 the growth of Halobyssits moniliforniis in a saturated solution 

 of sodium chloride, and the existence of living fungi in solutions 

 of salts of copper. 



NO. 1272, VOL. 49I 



Sir Douglas Galton calls attention to an important and 

 extensive investigation being carried out by the committee on 

 the mental and physical condition of children, of which he is 

 the chairman. About 50,000 school children have been seen 

 individually, and from the notes taken it appears that about 

 seven per cent, were mentally dull, and that sixteen per looo 

 require special care and training. It is proposed to report upon 

 100,000 children if the necessary funds are forthcoming, and 

 for this an appeal is made to all who, while desiring progressive 

 education, also desire that the training of children should be 

 conducive to the development of both sjund bodies and brains. 



Mr. C. a. Barber, Superintendent of Agriculture for the 

 Leeward Islands, contributes to the Leeiuard Islands Gazette a 

 report on the diseases of the sugar-cane in the West Indies. It 

 refers chiefly to the insects whicti attack the canes, the various 

 stages of the different species being descriiied and figured. The 

 Kezv Bulletin for March contains also a correspondence on the 

 subject between the Director of the Gardens and the Director 

 of Forests and Gardens for Mauritius. This lefers to the 

 destruction of the crop by the parasitic fungus Trichospharia 

 Sacchari, which has apparently been introduced into Mauritius 

 from the West Indies. 



Th¥. Journal of the Royal Asiatic Society of Bengal for 

 November 27, 1893, contains an interesting article on the 

 "Blind Root-suckers of the Sunderbans," a tract of swampy 

 littoral forest occupying the southern portion of the Delta of the 

 Ganges. A large number of the trees which inhabit this area 

 are furnished with root-suckers in the form of woody processes 

 growing in an upward direction, and developed at irregular 

 distances along the whole course of the roots. They project 

 from one to three feet above the surface of the ground, and 

 apparently cease to grow when the apex has reached the level 

 of the highest spring-tides. The main object of these structures 

 is to protect the tree against the uprooting effect of violent 

 winds in the swampy soil ; but they also contain a system of 

 air-chambers for the aeration of the root. They never produce 

 buds. 



Readers of Hermann Midler's "Die Befruchtung der 

 Biumen," or its excellent translation by Prof. D'Arcy 

 Tho.npson, will remember its opening sentence: "It was not 

 until the close of the last century that the true purport and sig- 

 nificance of flowers began to be perceived. Christian Conrad 

 Sprengel seems to have been the first to view the subject in the 

 light of adaptation, and to show how all the colours, scents, and 

 singular forms of flowers have some useful purpose. His book 

 struck out a new path in botanical science, and its title, ' The 

 Secret of Nature revealed in the Formation and Fertilisation of 

 Flowers,' shows that the author was well aware of the impor- 

 tance of his discoveries." This work of Sprengel's, " Das ent- 

 deckte Geheimniss der Natur im Bau und in der Befruchtung 

 der Biumen," was published in Berlin in 1793, and for many 

 years has bean an exceedingly rare and costly book. In spite of 

 the teleological standpoint of all Sprengel's researches, it will 

 always be a book of interest and of reference ; we are therefore 

 glad that advantage has been taken of the centenary of its 

 appearance, to bring out a facsimile reprint, which has just 

 been published as one of Mayer an 1 Midler's " Wissenschaft- 

 liche Classiker in Facsimile-Drucken." The volume contains 

 224 quarto pages and twenty-five plates, and costs only eight 

 marks. 



In a paper, " Influenza della luce solari sulle acque di 

 rifiuto," Dr. Procacci contributes to the Annali deW Istituto 

 a'lgiene Sperimentak di Roma, vol. iii. p. 437, the results of 

 his numerous investigations on the bactericidal action of sun- 

 shine on the microbes normally present in drain-water. 



