September 19, 1912] 



NATURE 



91 



number of scientific men on what inventions they 

 considered to be the " seven wonders of tlie modern 

 world," and for this purpose a list of numerous inven- 

 tions was circulated, from which seven had to be 

 selected. The result is published in the August 

 number, and the seven inventions which received the 

 highest number of votes are as follows : — Wireless, 

 telephone, aeroplane, radium, antiseptics and anti- 

 toxins, spectrum analysis, X-ray. 



We learn from the daily Press that considerable' 

 anxiety is felt in France regarding the frequent deaths 

 that have recently occurred through eating poisonous 

 fungi. Three precautionary measures are suggested. 

 One is to avoid gathering mushrooms having a per- 

 sistent volva at the base of the stem ; another is to 

 boil every mushroom in water with a little salt ; and 

 a third is to have some animal charcoal at hand to be 

 swallowed when a case of poisoning occurs. It is 

 stated in the notices that no species is poisonous in 

 which the volva is absent. It would be, however, 

 wrong to regard all such species as esculent, for 

 several well-known kinds having this characteristic 

 certainly produce temporary, if not fatal, poisoning, at 

 least unless subjected to prolonged boiling. 



Two useful lists of South African plants have 

 recently been published. Mr. J. Burtt-Davy and Mrs. 

 Reno Pott-Leendertz (Annals of the Transvaal 

 Museum, vol. iii.) have compiled a "first check-list" 

 of the flowering plants and ferns of the Transvaal 

 and Swaziland, enumerating about 3300 species. Mr. 

 F. Eyles (South African Journal of Science, vol. viii.) 

 gives a preliminary list of the plants of southern 

 Rhodesia, comprising about 1700 flowering plants and 

 ferns. 



A NEW and curious species of " ground bean " 

 (Kerstingiella geocarpa, Harms) from tropical West 

 Africa is described and figured in the Kew Bulletin, 

 No. 5, 1912. When the flowers are fully developed 

 they are close to the ground, and after fertilisation 

 the hitherto short stalk of the ovary lengthens into 

 a long " carpopodium," which turns down and drives 

 the young pod into the ground, where it matures. 

 The same number contains a description and fine 

 plate of a remarkable new spurge (Euphorbia miilti- 

 ceps, Berger) received at Kew from South Africa ; 

 it resembles a green pineapple with a number of 

 spikes protruding irregularly from it, the stout fleshy 

 axis being densely covered with short coral-like hori- 

 zontal branches — the spikes are barren inflorescences, 

 but no flowers have been seen. There is also a useful 

 compilation of the various timbers and trees to which 

 the terms tulipwood and tulip tree have been applied, 

 just as other names (gum, rosewood, cedar, pine, 

 mahogany, &c.) are indiscriminately applied to diverse 

 limbers and trees. 



Mr. Cecil H. Hooper has contributed to Irish 

 Gardening for June and July an account of some 

 interesting experiments on the pollination of hardy 

 fruits, made by himself, Mr. F. Chittenden, and 

 others. These experiments were made in order to 

 ascertain whether fruits can set and mature without 

 NO. 2238, VOL. 90] 



the aid of bees, whether mature fruit can be obtained 

 by pollination with the pollen of the same variety or 

 the same flower, and whether better fruits result from 

 pollination with pollen of another variety. It was 

 found that gooseberries and currants, raspberries and 

 loganberries, though freely self-fertile, set better fruit 

 when visited by bees ; that strawberries are apparently 

 to some extent wind-pollinated, though this needs con- 

 firmation. As is well known, more or less complete 

 self-sterility is common among the many varieties of 

 cherry, .plum, apple, and pear ; in the majority of 

 cases pollen from another variety is essential for fruit 

 formation. Details are given of numerous interesting 

 results obtained by covering otherwise untouched 

 flowers vi'ith muslin bags, by brushing with pollen from 

 the flower's own anthers or from those of other plants 

 of the same variety, and by pollination with pollen 

 from other varieties. In connection with the inter- 

 planting of different varieties in orchards, lists are 

 given according to the times of flowering. The 

 author estimates that about 80 per cent, of the pol- 

 lination of hardy fruits is done by the hive bee, about 

 15 per cent, by the various humble bees, and the 

 remainder by miscellaneous insects. 



The meteorological year-book for Bremen, igii, one 

 of the regular German series, contains two important 

 summaries in addition to the observations for the year 

 in question : — (i) A discussion of the daily maximum 

 and minimum temperatures for 1890-1910 (twenty-one 

 years) by Mr. J. Siedenburg ; and (2) monthly tables 

 of the climate of Bremen for 1876-1910 (thirty-five 

 years). This long series gives an absolute maximum 

 temperature of 93'9° in May and an absolute minimum 

 of —130° in December, but a reading of —iyi° is 

 quoted as having occurred on January 23, 1823. The 

 heat and drought of 191 1 lasted from July 4 to Sep- 

 tember 27 (twelve weeks). Prof. Grosse ascribes the 

 abnormal conditions principally to the shifting of. the 

 .Azores pressure maximum to the north-east, and 

 possibly to some extent to the approximate occurrence 

 of the minimum sunspot period. 



In the AM dei Lincei, xxi. (2), 2, Prof. Augusto 

 Righi describes experiments on the convection of ions 

 produced by magnetic or magneto-kathodic rays. 

 According to the author's hypothesis these rays cause 

 some of the electrons to unite with positive ions, the 

 combination behaving like a double star or the system 

 formed by a planet and its satellite. Once formed, 

 they are carried by magnetic action from regions of 

 greater to regions of lesser magnetic force, where the 

 elements again frequently become dissociated. To 

 dectect the presence of these ions. Prof. Righi makes 

 use of a small cylinder of paper suspended by a fibre 

 in the magnetic field generated by a second induction 

 coil. According to theory the ions, by their impact 

 on the cylinder, should cause the latter to rotate in 

 the same direction as the magnetising current of the 

 coil, and this was observed to be the case. 



Certain formulae relating to the pressure of fluids 

 on oblique planes have been recently quoted as 

 " .•\vanzini's law." Col. de Villamil has made several 

 inquiries as to where these laws were published, and 

 having failed to obtain the information from others. 



