November 3, 1898] 



rJA TURE 



• <Jynamometer apparatus used in the experiments measured ami 

 recorded (i) the pull or push exerted by the engine on the 

 train ; (2i the distance run ; (3) the speed ; (4) the places of 

 starts, stops, and stations ; and (5) the time when starts and 

 stops were made, and when stations were passed. The horse- 

 power shown by the indicator diagrams differed from that 

 recorded by the dynamometer, which was in a separate car. 

 Usually, however, the ratio between the two horse-powers 

 ■did not vary much. On an average the dynamometer horse- 

 power was equal to appro.ximately 64 per cent, of the indicated 

 horse-power. Thus about 36 per cent, of the driving power 

 was absorbed by the engine and tender. 



Mr. N. R. Harrington and Dr. Reid Hunt have arrived 

 in New York from the Nile valley, where they have been several 

 months collecting Polypterus and other interesting and valuable 

 cytological material. We learn from Science that the chief 

 object of the expedition was to procure the life-history of 

 Polypterus and its bearings upon the problem of the relation of 

 the Crossopterygian fishes to the Amphibia. In the last few 

 years the former theory that Amphibia sprang from Dipnoan 

 fishes has gradually given way to the present view that Dipnoi 

 are to be regarded as parallel to Amphibia from a common 

 Crossopterygian origin. Several very successful expeditions 

 have been sent out to procure material for the embryology of 

 Dipnoans, notably that of Prof. Richard Semon from Jena, and 

 that of Mr. Graham Kerr from the University of Cambridge. The 

 former secured the complete life-history of Ceratodus, and the 

 latter brought back the embryology and complete life-history of 

 Lepidosireii^ a South American form. But before the recent 

 expedition nothing had been done upon the development of 

 Polypterus, because of the exceptional difiSculties which stood in 

 the way of procuring material. Messrs. Harrington and Reid 

 found that the fish did not occur in Lake Menzaleh during the 

 low Nile period, but they came across several Polypterus near 

 Ras-el-Ghelig. The best Polypterus fishing ground, not closed 

 on account of the Sudan campaign, was at Mansourah, forty 

 miles from the sea ; and the party settled there for the summer. 



The attention of botanists has of late years been turned to 

 the biology of ferns, but there still remain a great many facts to 

 be explained, and questions to be solved. Dr. Aurelio de Gas- 

 paris, in a paper to be published in the Aiti of the Naples 

 Academy, has brought to light a large number of new facts 

 relating to ferns. Some of these relate to certain forms of dis- 

 semination not previously observed, others to the trophilegic 

 action of the fronds, in connection with which certain arrange- 

 ments have been observed, destined to facilitate the passage of 

 water to the roots. The author has also discovered two new 

 cases of myrmecophily, as well as a number of cases of acar- 

 ophily among ferns, many of them very evident and easy of 

 observation. 



An interesting addition to the list of myrmecophilous plants 

 furnished with so-called "extra-nuptial" nectaries is given by 

 Prof. Federico Delpino in the Reudiconto of the Naples 

 Academy, iv. 7. In the Botanical Gardens at Naples about 

 seven or eight plants have recently been observed to possess these 

 glands, which differ from the ordinary melliferous glands in not 

 being associated with the floral organs and being provided for the 

 purpose of attracting ants instead of for promoting fertilisation. 

 The newly-observed cases occur in Cardantiiie cheledonia, L. , 

 Lilium crticeum, L., Dyekia regalis and D. rcmoti flora, a species 

 of Aechmea, Iris foetidissimu, L. , and Vicia serratifolia, Koch. 

 The families of Cruaferae and Bromeliaceae are thus added 

 to the fifty-eight families previously known to contain species 

 furnished with the glands in question. 



In a paper, published in the Sitzungsberichte of the Berlin 

 Academy of Sciences, Dr. K Johow states his belief that the 

 NO. 15 I 4, VOL. 59] 



number of flowers pollinated by the agency of birds is much 

 smaller than is often stated. Humming-birds, in particular, 

 since they feed entirely on insects, and not on nectar, play but 

 a small part in the carriage of pollen. He describes, however, 

 an unquestionably ornithophilous flower in a Chilian Bromeliad, 

 Paya chilensis. The " nectar " in this flower is exceedingly 

 abundant, but is not attractive to insects, being very watery, and 

 containing but little sugar. It is, however, eagerly drunk by 

 humming-birds, but more especially by the " Chilian starling,'' 

 Curaeus aterrimuus ; and these birds get their heads plentifully 

 besprinkled with the pollen, which they then carry to other 

 flowers. 



ProPi Ramsay has an article on the kinetic theory of gases 

 and some of its consequences in the November Contemporary. 

 He explains Dr. Johnstone Stoney's application of the kinetic 

 theory to the atmospheres of planets and satellites, and then 

 considers the recent discoveries of gaseous constituents of our 

 own atmosphere, with special reference to the new element 

 "neon." The facts dealt with are summed up as follows: 

 " We have seen, then, that the discovery by Lord Rayleigh of a 

 discrepancy in the density of atmospheric nitrogen has resulted 

 in the discovery of a new constituent of air, argon ; its dis- 

 covery has led to that of a constituent of the solar atmosphere, 

 helium ; speculations on the ultimate nature and motion of the 

 particles of which it is believed that gases consist has provoked 

 the consideration of the conditions necessary in order that 

 planets and satellites may retain an atmosphere, and of the 

 nature of that atmosphere ; the necessary existence of an un- 

 discovered element was foreseen, owing to the usual regularity 

 in the distribution of the atomic weights of elements not being 

 attained in the case of helium and argon ; and the source of 

 neon was therefore indicated. This source, atmospheric air, 

 was investigated, and the missing element was discovered." 



The expressions for the work done in magnetising a body 

 have been given by Mascart and Joubert and Prof. J. J. Thomson, 

 by Prof. Ewing, and by Prof. .-Vscoli respectively in three different 

 forms, all of which lead to the same results when applied to 

 closed cycles, but differ in the values they give for the work 

 done in an open transformation. An interesting examination of 

 these formula; is given by Signor Guido Grassi in the Rendiconta 

 of the Naples Academy, vi. 7. The author finds that Ewing's 

 formula {l/47ryHrfB represents the general expression of the 

 total work of magnetisation ; thatyHrfl represents the differ 

 ence between the total work of magnetisation and the work 

 which would have to be expended in order to create the mag- 

 netic field if the latter did not contain any bodies of magnetic 

 permeability different to that of air ; and that the expression 

 fXdW. does not represent the work of magnetisation except in 

 the case of a closed cycle. 



Prof. B. O. Peirce and Mr. R. W. Willson have for 

 several years been engaged in an attempt to measure, by the 

 aid of the " Wall method," the thermal conductivities of certain 

 relatively poor conductors, and the variations of these conduc- 

 tivities with the temperature. The methods they have adopted, 

 and the results of a number of observations, are now published 

 in the Proceedings of the American Academy of Arts and 

 Sciences (vol. xxxiv. No. i, August 1898). In the present 

 paper the results are given of determinations of conductivities of 

 about twenty specimens of marble of different kinds, when 

 the faces of slabs of the material are kept at temperatures! 

 of about 18° C, and 45° C, compared with the conductivity 

 of a special brand of glass which appeared to be practically 

 constant within the limits of the measurements. It appears 

 that the conductivity of a specimen of marble at ordinary mean 

 temperatures may depend, to the amount of several per cent., as 



