January 26, 1905] 



NA TURE 



305 



ponsidered the most promising of the seedling varieties, 

 did not give such good results as in previous years, but 

 it appears to be cultivated with some success in the rather 

 light soils in the parish of St. Philip. 



The Barbados Official Gazette of December 19, 1904, 

 contains some correspondence relating to Cassava poison- 

 ing. Mr. Briggs, one of the district coroners, noted to 

 the Colonial Secretary that witnesses in inquest cases 

 frequently assert that if roasting and poison cassava grow 

 closely side by side, the roasting cassava takes up some 

 of the poison from the poison cassava ; also that the 

 roastingf cassava gets a "spring in it," and that makes 

 it poisonous. The Colonial Secretary submitted the note 

 to Sir Daniel Morris, who replied that (i) " there can be 

 no direct connection between the two plants, and it is 

 impossible that the poison can pass through the soil from 

 the poisonous cassava to the sweet," and (2) "if by the 

 ' spring in it ' is meant that the plant starts into second 

 growth after heavy rain, it is probable that certain changes 

 may take place inducing an increase of the poisonous 

 quality." What probably happens when persons die from 

 eating sweet or roasting cassava is that it is either too old 

 or it has not been sufficiently cooked to drive out all the 

 acid. It is only really wholesome when the roots are not 

 too old, and when they have been cooked until they are 

 quite soft. If the centre is hard it is probably more or 

 less poisonous, and should not be eaten. Even properly 

 cooked cassava which has been allowed to become cold is 

 not fit to eat unless it is cooked a second time. 



Beckelite, a new mineral species named in honour of 

 Prof. F; Becke, of Vienna, is described by Prof. J. 

 Morozewicz in the December (1904) Bulletin of the Cracow 

 Academy of Sciences. It occurs as an accessory constituent 

 of a dyke-rock composed of albite, nephelite, oegirite, and 

 magnetite in the elffiolite-syenite complex near Mariupol, on 

 the Sea of Azov. The wax-yellow octahedral or rhombic- 

 dodecahedral crystals resemble pyrochlore in general 

 appearance and physical characters, though the somewhat 

 indistinct cleavage is cubic instead of octahedral. 

 Chemically, however, the new mineral is quite distinct 

 from pyrochlore, containing 17- 13 per cent, of silica and 

 65.31 per cent, of rare earths, with no niobium or tantalum. 

 The formula is Ca3(Ce,La,Di),SijO|5, which presents a 

 certain resemblance to the garnet formula with rare earths 

 in place of alumina. From analogy to calcium " alumo- 

 silicate," the new mineral is described as a calcium cero- 

 lanthano-didymo-silicate. 



For the twenty-second time, the climatological records 

 of the British Empire are summarised in the current 

 number of Sy^noiis's Meteorological Magazine, viz. for the 

 year 1903. The stations number twenty-five, but, as the 

 editor points out, it is impossible to represent the average 

 conditions of the climate of the Empire by so small a 

 number of stations, however well distributed. Adelaide, 

 which has almost constantly held the first place in the 

 summary for extreme maximum temperature, now, as in 

 1902, gives way to Coolgardie, in Western Australia, 

 where the shade temperature reached ii3°-4 on January 27; 

 the lowest shade temperature was — 6o°-8 at Dawson on 

 January 26. Dawson had also the greatest yearly range 

 (i5o°-3). The greatest mean daily range was 23°.5 at 

 Winnipeg, and the least 8°-5 at Hong Kong. London had 

 the highest relative humidity (82 per cent.) and Adelaide 

 the lowest (62 per cent.). The greatest rainfall, 93'67 

 inches, was recorded at Hong Kong, and the least, 10-74 

 inches, at Dawson. We may mention, incidentally, that 



NO. 1839, VOL. 71] 



the present number of the magazine is the largest since 

 its foundation in 1866 ; we hope to refer shortly to another 

 of the interesting articles that it contains. 



We have received the Journals of the Meteorological 

 Society of Japan for October and November last. They 

 contain (as we see from the English titles) several interest- 

 ing articles in Japanese. There is also one in English, on 

 the duration of rainfall, by T. Okada. The object of the 

 author is to show that Dr. Koppen's formula for the 

 calculation of the probable duration of rainfall in a month, 

 or any interval of time, from three or six observations 

 daily, holds good for all climates. The calculation is very 

 simple, and the formula in question, (r/njN, is contained 

 in an article by Dr. Koppen in the Austrian Meteor- 

 ologische Zeitschrift for 1880 ; n is the total number of 

 observations, r that of observations with rainfall, and N 

 the total number of hours in a month (or other period). 

 The author shows that the duration of rainfall, computed 

 from tri-daily observations, does not differ materially from 

 that computed from hourly observations — in the annual 

 mean at most 4 per cent., and in the monthly mean 18 

 per cent. In the majority of cases the differences are much 

 less; the method gives more approximate results than an 

 ordinary self-recording rain-gauge, owing to the usual 

 want of sensibility of such instruments. 



In the Zeitschrift fiir physikalischen und chemischen 

 Unterricht, xvii., 5, Mr. Walter Stahlberg, of Steglitz, 

 gives an account of the Zeiss " Verant " by which photo- 

 graphs are made to stand out in natural relief with mon- 

 ocular vision. The apparatus can hardly be correctly de- 

 scribed as a stereoscope, since one of the most important 

 features of the stereoscope depending on binocular vision 

 is absent. The Verant is a single lens, the focal 

 length of which should be equal to that of the camera 

 used in taking the photographs, and this lens is convexo- 

 concave, so that the axes of the pencils from different 

 parts of the picture meet in the eye. From Mr. Stahl- 

 berg's account, we think the principle of the Verant may 

 be roughly explained by the following illustration : — When 

 a photograph of cloisters is taken from one corner in the 

 interior the photograph gives the impression that the two 

 colonnades meet at a very acute angle instead of at right 

 angles. If the picture were seen through the Verant the 

 angles would appear correct as they would to a person 

 standing in the cloisters themselves. The now old- 

 fashioned graphoscope appears to have had a somewhat 

 similar purpose. 



Two papers which are of importance in the study of 

 superfusion phenomena are published by Drs. Tullio 

 Gnesotto and Gino Zanetti in the Atti of the Royal 

 Venetian Institute (1903, vol. Ixii., p. 1377)- By 

 means of a modified ice calorimeter, the variation of the 

 specific heat of superfused liquid sodium thiosulphate at 

 temperatures between 0° C. and the melting point of the 

 salt, 48°-8 C, was determined, the observations being also 

 extended above this temperature up to 100° C. On calcu- 

 lating the specific heat at all temperatures within this 

 range, it is seen that in the neighbourhood of the melting 

 point a sudden diminution in its value occurs, but that 

 slightly above this temperature the specific heat again 

 increases, so that the curve resumes the same direction 

 that it had below the melting point. The latent heat of 

 fusion of the salt 3t 0° C. Was also determined. 



A VALUABLE paper On the properties of chrome-vanadium 

 steels was read before the Institution of Mechanical 

 Engineers on December 16, 1904, by Captain Riall Sankey 



