March 24, 1898] 



NATURE 



491 



brought off safely. Since leaving Mocha, the Pola has made 

 valuable observations, chiefly geological, at a number of points 

 along the coast, and amongst the islands. 



An instance of the service which the Department of Scientific 

 and Technical Research of the Imperial Institute is able to 

 render appears in the number of the British Central AJrica 

 Gazette, which has just reached this country. A specimen of 

 limestone found on Kilwa Island, Lake Shirwa, was sent to the 

 Institute for an opinion as to its value, and Mr. Wyndham R. 

 Dunstan sent the following report upon it : — *' The sample of 

 limestone from Kilwa Island, which is used at Zomba for making 

 lime, turns out to be calcium carbonate— Iceland spar. It con- 

 tains small quantities of iron and magnesium, and also of 

 phosphate. This last constituent, though minute (o*i percent.), 

 should be borne in mind in connection with the possible use of 

 the mineral, either burnt or in its natural state, as a manure. 

 Another point, to which I think it would be well to direct 

 attention, is the value of large, well-formed, colourless trans- 

 parent, rhombohedral masses of the spar. These are employed 

 in the construction of certain optical instruments, and I was in- 

 formed by one of the principal manufacturers not long ago that 

 the supply of these crystals is now very scarce." The Gazette 

 states that, on receipt of this information, the Acting Com- 

 missioner took steps to procure and send home for valuation 

 transparent specimens of this crystal. 



In a presidential address to the Conchological Society, pub- 

 lished in the January number of the Journal of Conchology, 

 Prof. Hickson offers a suggestion to explain the untwisting of 

 the body which has admittedly taken place in certain groups 

 of Gastropod Mollusca. The asymmetry of the Gastropod body 

 was clearly brought about by the acquisition of a spire-like 

 shell, into which its possessor could completely withdraw. 

 Such a shell, however, though advantageous as a protection, is 

 an obstacle to locomotion ; therefore, if the Gastropod body 

 could be protected in another way, the raison d'etre for a 

 spiral shell would disappear. Any increase in the size of the 

 foot, bringing about increased powers of locomotion, would be 

 an advantage to the species in giving it a wider range ; and, 

 to obviate the disadvantage of exposing the body to the possible 

 attacks of enemies, an obnoxious or poisonous fluid might be 

 secreted. In support of this view, Prof. Hickson states that 

 among Opisthobranchs there is actually a series of forms show- 

 ing a gradual diminution in the twist of the shell and a corre- 

 sponding increase in the size of the foot ; and, in addition, 

 ■ points out that some Nudibranchs have been shown to be dis- 

 tasteful to fishes. 



In Bulletin ii, new series, of the U.S. Department of Agri- 

 culture (Division of Entomology), Mr. L. O. Howard describes 

 the introduction and spread of the Gipsy Moth (Porthetria 

 dispar, L.) in Massachusetts, and the means employed for its 

 extermination. This species, injurious on the Continent, but 

 now apparently extinct in Great Britain, was introduced into 

 Massachusetts in 1869 by the escape of examples imported for 

 experiments in silk-growing. Becoming acclimatised in scrub- 

 undergrowth, it multiplied slowly in spite of efforts made to 

 check it, becoming a serious pest by 1889. Since that time its 

 range has extended to about 220 square miles, within which area 

 it has done enormous destruction by the defoliation of deciduous 

 trees. The State has fought it energetically, expending in the 

 the last eight years as much as 725,000 dollars, in addition to 

 40,000 dollars allowed by Congress. In some years, however, 

 the grants have been made too late to allow the work of de- 

 struction to be adequately proceeded with. The chief measures 

 relied on are spraying the foliage with lead arsenate, destruction 

 of the eggs with creosote, grease-banding the trunks to prevent 

 caterpillar ascent, or tying them round with strips of coarse 



NO. 1482, VOL. 57] 



canvas (burlap), under which the caterpillars assemble, and 

 whence they can be collected. Mr. Howard, who claims that 

 this will rank as " one of the great experiments in economic 

 entomology in the history of the world," estimates that more than 

 nine tenths of the colonies, large and small, existing in 1891, 

 have been exterminated ; and, except for the difficulty of dealing 

 with woodlands, there appears to be no reason why continuance 

 of the present treatment should not ultimately achieve the total 

 extirpation of the insect. 



Prof, Putnam has called our attention to an error in the sum- 

 mary of his paper on the magnetic survey of Greenland (Nature, 

 February 10, p. 347). He points out that the balancing ring em- 

 ployed was of appreciable width, and that, therefore, the formula 

 used in computing the moment of inertia was correct. In this 

 Prof. Putnam is quite right, and the writer of the notice regrets 

 that he did not follow the description of the instrument with 

 sufficient care. As stated in the article, the numerical results 

 are in no way affected. 



A NEW periodical — The Wide World Magazine — has just 

 been commenced by Messrs. Geo. Newnes, Ltd. The first 

 number contains several instructive articles, all of which are 

 illustrated by striking photographs. Probably no more remark- 

 able collection of pictures have ever appeared than are repro- 

 duced in this new magazine. Among the contents we notice a 

 number of pictures of scenes and people in New Guinea, con- 

 tributed by Prof. A. C. Haddon ; photographs of various 

 devotees ; an article by Dr. Nansen, entitled " How the North 

 Pole will be reached" ; a number of interesting photographs of 

 scenes in China, by Mr. J. Thomson ; reproductions of several 

 of Mr. Saville- Kent's curious photographs ; and some memories 

 of Navarino, by Admiral Sir Erasmus Ommanney. The mag- 

 azine is distinctly in advance of the general type of popular 

 periodical, and its contents bear out its motto that " Truth is 

 stranger than fiction." 



The additions to the Zoological Society's Gardens during the 

 past week include a Mexican Deer (Cariacus mexicaniis, (J ), a 

 Reddish Brocket {Cariacus rufinus, (J ), a Globose Curassow 

 {^Crax globicera, 9 ) from British Honduras, presented by H.E. 

 Colonel Wilson, C.M.G. ; two Zebus {Bos indicus, <J ?) from 

 India, presented by Commander George Stevenson ; a Macaque 

 Monkey [Macacus cynomolgus, 9 ) from India, presented by Mr. 

 M. Lyons ; a Senegal Parrot (Paocepkalus senegalus) from 

 West Africa, presented by Miss L. Firmin, a Common Fox 

 (Cams vtilpes, <J ), British, presented by Miss Heard ; a Malayan 

 Paradoxure (Paradoxurus hermaphroditus) from Singapore, a 

 Hairy Armadillo {Dasypus villosus) from La Plata, a Grand 

 Eclectus (Eclectus roratus) from Moluccas, deposited ; a Man- 

 churian Crane {Grus joponensis), four Gold Pheasants {Thau- 

 maleapicta, 6 6 9 9) from China, two Argus Pheasants (^r^«5 

 giganteus, 6 9) from Malacca, two Horned Tragopans {Ceri- 

 ornis satyra, 6 9 ) from South-east Himalayas, two Lineated 

 Pheasants {Euplocatnus lineatus) from Tenasserim, two Somali 

 Ostriches {Struthio niolybdophanes,i 9 ) from Somali-land, two 

 Many-coloured Parrakeets ( Psophotus multicolor), four Spotted- 

 sided Finches {Amadina lathatni) from Australia, a Snow 

 Bunting {Plectrophanes nivalis), European ; two Lapwings 

 ( Vanellus cristatus), British, purchased ; seven Baer's Ducks 

 {Fuligula baeri) from India, received in exchange. 



OUR ASTRONOMICAL COLUMN. 

 Magnitudes OF 1081 Southern Stars. — During a voyage to 

 Australia (1885-86), round the Cape of Good Hope and back by 

 the Red Sea, including a stay of two months in Australia, Mr. 

 Stanley Williams was able to make a very useful catalogue of 1081 

 stars lying between 30° south declination and the South Pole. 



