472 



NATURE 



[September i6, 1897 



In the Atti dei Lined, vi. 4, Prof. Domenico Mazzotto gives 

 a continuation of his observations on the electro-magnetic in- 

 dices of refraction of woods. The object of the new experi- 

 ments was to ascertain whether the principal indices of refraction 

 were proportional to the square roots of the dielectric constants 

 in the same directions, in accordance with Maxwell's theory. In 

 the case of beech (and presumably other woods) this relation 

 was found to be satisfied. On drying the wood, both the 

 dielectric constants and the indices of refraction diminished 

 correspondingly. 



In the Rendiconto of the Naples Academy (iii. 7), Dr. R. V. 

 Matteucci announces the discovery for the first time of the 

 elements iodine and bromine among the products of the 

 fumaroles of Vesuvius. It will be remembered that only 

 quite recently the same author discovered selenium in a similar 

 locality. — Prof. Domenico de Francesco gives an elegant mathe- 

 matical investigation of the equations of vertical motion of a 

 balloon in free air on the assumption of Newton's law of resist- 

 ance. — Prof. E. Villari gives a note on the discharging property 

 produced in gases by certain compounds of uranium, first 

 discovered by Becquerel. 



Several partial accounts of Prof. Vicentini's valuable micro- 

 seismograph have already appeared, but for the first time a com- 

 plete description is given in a memoir by Dr. G. Pacher [Atti 

 del K. 1st. Veneto di scienze, t. viii., 1897, pp. 1-62). The in- 

 struments described are the original form of the microseismo- 

 graph, in which the length of the pendulum is 1*5 m., and its 

 mass 100 kg., and the latest form, in which the length is 107 m. 

 and the mass 408 kg. Detailed instructions are given for erecting 

 the apparatus in a suitable place, for putting the different parts 

 together, preparing the smoked paper, &c. There are also brief 

 accounts, with useful bibliographies, of other instruments, such 

 as the horizontal pendulums of von Rebeur-Paschwitz and Milne, 

 the bifilar pendulum of H. Darwin, the vertical pendulums of 

 Agamennone and Cancani, and the geodynamic levels of 

 Grablovitz. 



A PHYSICAL theory of the electrical phenomena of the higher 

 atmosphere is briefly described by M, Marcel Brillouin in the 

 Revue Gen^rale des Sciences (August 30). It is now well known 

 that any metallic body charged negatively, loses its charge when 

 exposed to ultra-violet light. Experiments carried out in the 

 physical laboratory of the Ecole Normale in Paris have shown 

 that dry ice behaves like a metal, when charged with negative 

 electricity and exposed to ultra-violet radiations. When the ice 

 has a film of water upon it, however, the loss of electricity is 

 extremely small. As cirrus clouds consist of ice needles, and 

 receive ultra-violet radiations from the sun, negative electri- 

 fication may pass from the needles into the surrounding air, 

 leaving the cloud particles charged positively. This is the 

 basis of the theory, which is summed up by M. Brillouin as 

 follows: (i) atmospheric electricity is produced by the action 

 of ultra-violet solar radiations upon the ice needles in cirrus 

 clouds ; (2) the initial electrical field is produced by the move- 

 ments of the higher regions of the atmosphere relatively to the 

 earth's magnetic field. 



The Bulletin de la Societe de Geographie contains a suggestive 

 paper by Prof. J. Thoulet on the great need for better maps of 

 the seas and oceans. Maps of those regions are no longer 

 exclusively of interest to the navigator — almost every scientific 

 man is now more or less concerned with oceanography in some 

 of its aspects, and every day raises new practical problems con- 

 nected with cables, fisheries, submarine mines, &c. — nevertheless 

 the best accessible sea-maps are small of scale and mostly out of 

 date. Oceanographers know that the average current-chart, 

 faithfully copied from one atlas to another, is a disgrace to 

 modern knowledge, but it may be doubted if the time is yet ripe 

 for an elaborate " Sea Atlas " of large-scale maps. The scheme 

 NO., 1455. VOL. 56] 



proposed and ably worked out by Prof. Thoulet in the second 

 part of his paper cannot, however, be undertaken too soon. It 

 is proposed, by careful drawing of lines on the large-scale charts, 

 to prepare accurate contour maps of the whole of the sea- 

 bottom within 200 metres of the surface, and then, by enlisting 

 volunteer observers, to collect sufficient material to allow of 

 accurate lithological classification of the deposits on the con- 

 tinental shelf. The distribution of these deposits could be 

 shown by colouring on the contour charts, and we should thus 

 be put in possession of an accurate representation of the relief 

 and geological formation of one of the most interesting and 

 important regions of the globe. Prof. Thoulet suggests that the 

 deposits should be arranged under four headings: "sand," 

 "muddy sand," "sandy mud," and "mud"; the different 

 sorts being determined when necessary by mechanical analyses. 

 The paper contains details referring to the French coasts, but 

 the work is even more needed in this country. 



The publication is announced of a new " Journal of American 

 Science," under the name Orcutt. The Journal of Botany 

 quotes the following paragraph from the prospectus : — " No 

 complimentary copies ; no free samples ; no exchanges ; no 

 advertisements in the text ; no premiums ; no discount to 

 agents ; the whole income going to make it better and larger. 

 Botany and horticultural science will receive the greatest atten- 

 tion in the first numbers ; botanists are invited to publish new 

 species in its pages." 



The Report from the Curator, Lieut. -Colonel King, of the 

 Royal Botanic Garden, Calcutta, for the year 1896-97, is one of 

 considerable disaster ; both that garden and the Lloyd Botanic 

 Garden at Darjeeling having suffered much from the drought of 

 that year, following the drought of 1895-96. Notwithstanding 

 this, much useful work has been done in the cultivation of 

 economic plants, the investigation of the flora of British India, 

 and the enrichment of the herbarium. A monograph has been 

 published of the Indian species of bamboo, by Mr. J. Sykes 

 Gamble. 



The following are among the papers and other publications 

 which have come under our notice within the past few days :— 

 " On the Magnetic Properties and Electrical Resistance of Iron 

 as dependent upon Temperature," by Dr. David K. Morris. 

 This paper was read before the Physical Society last May, and 

 is published in the Philosophical Magazine for September. The 

 general character of the work and results are described in 

 Nature of May 20 (p. 70).— Prof. George 11. Barton has sent 

 us a report, reprinted from the Technology Quarterly (June), 

 upon his " Glacial Observations in the Umanak district, Green- 

 land." Prof. Barton was a member of the Boston party on the 

 sixth Peary Expedition to Greenland, and his report is the 

 second which has been published upon scientific work accom- 

 plished during the expedition. — " A Method of determining 

 Magnetic Hysteresis Loss in Straight Iron Strips," by Prof. J. A. 

 Fleming, F.R.S., read before the Physical Society on June 11 

 (see p. 166), and reprinted from the Philosophical Magazine for 

 September. — The seventh and eighth parts of vol. ii. of Prof. G. 

 O. Sars' "Account of the Crustacea of Norway" have just 

 been issued by the Bergen Museum. The Desmosomid?e and 

 part of the family of Munnopsidse are described and illustrated. 

 The additions to the Zoological Society's Gardens during the 

 past week include a Smooth-headed Capuchin {Cebus monachus) 

 from South-east Brazil, presented by Mr. W, R. Routledge ; a 

 Brown Capuchin {Cebus fatttellus) from Guiana, presented by 

 Mr. C. Hardy ; a Common Marmoset (Hapale jacchtts) from 

 South-east Brazil, presented by Mrs. C. J. Anson ; an Ivory 

 Gull (Pagophila eburnea) from the Arctic Regions, presented by 

 Mr. F. G. Jackson ; a Chameleon {Chamceleon vttlgaris) from 

 North Africa, presented by Mr. H. du Domaine ; a King 

 Parrot {Aprosmicius cyanopygius) from Australia, presented by 



