May 19, iQio] 



NATURE 



347 



Dr. D. Hooper in the Journal of the Asiatic Society of 

 Bengal (vol. v., No. 9). It has been identified as the 

 secretion of Phromnia marginella, an insect passing in 

 India under the name of the ghost bug. The substance 

 contains sugar in the form of dulcitol, which the author 

 refers to a special secretion in the plant. 



An article in Engler's Botanische Jahrbiicher (vol. xliv., 

 part i.) b}' Dr. R. Knuth, on the formation of hybrids in 

 the genus Pelargonium, should be interesting to horti- 

 culturists and botanists alike. The large number of 

 Pelargonium hybrids contrasts greatly with the three 

 hybrids known for Geranium and two for Erodium. It is 

 strange to find that five sections of the genus furnish no 

 hybrids, while crosses between species in different sections 

 are not uncommon. The author remarks that, as a rule, 

 there is no fusing of parental characters, but more often 

 one supplies the leaf and the other the flower characters 

 in the hybrid. The " English " pelargoniums, known in 

 this country as decorative or fancy, are attributed to crosses 

 between grandiflorum of the section Polyactium, and the 

 species cuctiUatum, cordatum, and angulosum of the section 

 Pelargium. Dr. Knuth recognises the excellent work of 

 English horticulturists, and places a high value on the 

 classic work of Sweet on the Geraniaceae, published in 

 1815. 



The composition of Indian rice has been investigated by 

 Mr. David Hooper, and the results are published as No. 5 

 of the Agricultural Ledger. Rice cultivation is the most 

 important of the agricultural industries of India, more 

 than seventy million acres being annually under this crop. 

 There are a number of varieties of grain differing in size, 

 shape, colour, and other properties, not all being equally 

 suitable for culinary purposes. Thus a variety known as 

 kauk-nyin is- so glutinous that it v.'ill not stand the boiling 

 required by ordinary rice, but is made into various kinds 

 of puddings and sweetmeats. It is frequently boiled in 

 bamboo tubes, to be eaten cold by travellers; when re- 

 quired, the bamboo is peeled off, and a long roll of rice 

 appears which forms a palatable substitute for bread. 

 Taking the 159 samples as a whole, the percentage of 

 carbohydrate varied between 922 and 82-2, of protein 

 between 11-4 and 606, of fat between 36 and o-ii. The 

 fibre rarely exceeded i per cent., and was usually round 

 about 05 per cent. ; the ash usually fluctuated between 

 05 and 2 per cent. This series of analyses of rice is prob- 

 ably the most complete that has yet been executed. 



Prof. R. Marek contributes an important paper on 

 the position of the upper limit of the forest growth in the 

 eastern Alps, and its relation to the elements of climate, 

 to Petermann's Mitieilungen (p. 63). The general con- 

 clusion arrived at is that the importance of mean atmo- 

 spheric temperature has hitherto been greatly over- 

 estimated, and that such factors as rainfall and direction 

 and force of wind are essential causes determining the 

 altitude of the forest line. 



The Proceedings of the Royal Society of Edinburgh 

 (vol. XXX., p. 183) contain a paper by Dr. \V. A. Caspari, 

 of the Challenger Office, on the composition and character 

 of oceanic Red Clay. Dr. Caspari gives the results of 

 analyses of thirteen samples of Red Clay obtained from 

 the different oceans in depths varying from 1900 to 3100 

 fathoms, and discusses the peculiarities of each. It is 

 established, generally, that Red Clays originate, in the 

 main, from the degradation of acid and basic volcanic 

 glasses, and that the chemical processes involved cannot 

 differ in essence from those associated with the sub- 



NO. 2 1 16, VOL. 8^] 



aerial weathering of silicates. A feature of deep-sea 

 " weathering " is that it takes place under conditions 

 which admit of finality ; in the Red Clay areas there is a 

 temperature of 1° C. to 3° C, a pressure of 400 to 600 

 atmospheres, and a uniform medium, sea-water, which- 

 have scarcely changed for millions of years. As a result, 

 a degradation product of much the same composition is 

 found all over the globe, and it is to be obser\-ed that it 

 is a more acid silicate than the corresponding continental 

 material. 



The Bulletin of the Philippine Weather Bureau for 

 August, 1909 (recently received), contains an interesting^ 

 note on the frequency of local earthquakes in relation w^ith- 

 atmospheric pressure in Manila in 1902-8. As " local 

 earthquakes " are designated the so-called instrumental 

 earthquakes the records of which traced by the micro- 

 seismograph show that their point of origin was in the 

 locality, or very close to it. During the years under con- 

 sideration 796 such disturbances were recorded at the 

 observatory, and a table showing graphically their mean 

 hourly frequency exhibits clearly two principal maxima 

 and minima, and one secondary maximum and minimum. 

 When this curve is smoothed by showing the frequency 

 for three-hour periods, its parallelism with that of the 

 double daily oscillation of atmospheric pressure shov^-s that 

 " at Manila the highest pressures are more favourable to 

 the occurrence of instrumental earthquakes than low- 

 pressures." Prof. F. Omori, the eminent seismologist, 

 has attributed the reason of such parallelism to the fact 

 that in all probability these local earthquakes have their 

 origin at very shallow depths, and may be closely connected 

 with daily changes of pressure exerted by the atmosphere 

 on the earth's crust (see Bulletin of the Imperial Earth- 

 quake Investigation Committee, Japan, vol. ii., p. 105). 



" The C.4USE of the Vertical Movements in the Atmo- 

 sphere " is the title of an interesting paper by Prof. W. 

 Trabert in the Siizungsberichte of the Vienna Academy of 

 Sciences of December 2, 1909. The inquiry is based upon 

 the observations of the uppar air made at Lindenberg 

 during the month of January, 1909. The diagrams, which 

 exhibit, inter alia, the isotherms and lines of equal potential 

 temperature up to an altitude of 5000 metres, show that 

 at times tongues of low temperature extend downwards 

 from the upper regions, and that others of higher tempera- 

 ture extend from below upwards, so that areas of high 

 and low temperatures become intermingled. Among the 

 results arrived at we' may mention the following : — In a 

 warm column of air the movement is upwards, and vice 

 versa. The ascending movement causes the air-pressure 

 to fall, and conversely. If cyclones and anti-cyclones are 

 thus caused, the air already cooled is dynamically carried 

 higher up, or the warmed air transferred further down- 

 wards, causing fresh vertical motion ; the origin of cyclones 

 and anti-cyclones is therefore thermic and dynamic. The 

 pendulum-like upward and downward movement of the air 

 is due to aqueous vapour, and the latent heat set free by 

 its condensation furnishes the energy for the maintenance 

 of the vertical circulation. 



The importance of the coherer as a detector in radio- 

 telegraphy amply justifies the large amount of attentioa 

 which has been paid to it by experimenters during the last 

 few years. Attention has been directed in these columns 

 to the work of Mr. G. W. Pierce (Physical Review, vol. 

 xxix., and references there) and of Mr. L. W. Austin 

 (Bulletin of the Bureau of Standards, vol. v.). In the 

 resutnd of communications made to the Soci6t^ fran^aise 

 de Physique on March 18 there are abstracts of two further 



