340 



NA TURE 



[Fed. lo, 1887 



to the North-West Australian coast and the Sooloo 

 Archipelago. 



Chapter XI. is devoted to a condensed account of the 

 pearl-fisheries of Ceylon and Southern India, and this is 

 followed by a resume of what is known respecting the 

 fisheries in the Persian Gulf, the Red Sea, on the west 

 coast of North America, and at the West Indies. Pearls 

 produced by shells which inhabit the rivers and lakes 

 of Cireat Britain and foreign countries are described 

 in Chapter XIV., and the artificial production of pearls by 

 the Chinese is also here referred to. The different kinds 

 of coloured pearls, and the mollusks which produce them, 

 are then treated of. In the succeeding chapter the most 

 famous pearls of both ancient and modern times are re- 

 counted, and the immense sums at which some of them 

 were valued are stated. Chapter XVII. gives the history 

 of the remarkable cluster of pearls known as "the great 

 Southern Cross pearl," which was exhibited in the West 

 Australian Court of the Colonial and Indian Exhibition, 

 and valued by the owners at 10,000/. The next and con- 

 cluding chapter is devoted to the value of pearls, and 

 shows how their worth has varied in this country at 

 different periods from 1671 to the present time. 



A map is then introduced showing the principal pearl- 

 ing regions. In an appendix, the works bearing on the 

 subject which have been consulted by the author are 

 enumerated, and a full index completes the volume. 



Mr. Streeter has brought together a large amount of 

 information which will be of interest to the general reader, 

 for whom especially, and not for the scientific, the work 

 has been written. The most original material is com- 

 prised in the part extending from the seventh to the tenth 

 chapter. The chapter devoted to the Sooloo Archipelago 

 contains some details which, although interesting in them- 

 selves, are rather foreign to the subject of the work. The 

 same observation applies to the account of the constella- 

 tion Crux Australis, or Southern Cross, introduced in the 

 seventeenth chapter. 



As far as we have noticed, the various opinions and 

 statements set forth in the work are mostly accurate. It 

 may, however, be questioned whether " there is per- 

 haps no instinct implanted in the human breast more 

 powerful than the love of admiration," for is not that of 

 self-preservation supposed to reign supreme .' We would 

 point out that the term Laincllibranchiata is now super- 

 seded by that of Pelccypoda, and with good and sufficient 

 reasons is adopted in the latest and best manuals on con- 

 chology. The bathymetrical range of bivalves far exceeds 

 the stated limit — 200 fathoms — specimens having been ob- 

 tained by the Challenger and other deep-sea exploring ex- 

 peditions in depths ranging as low down as 2900 fathoms. 



The book is printed in good legible type upon toned 

 paper, but the pictorial portion mars the rest. The plates 

 illustrating the Malleus, the Melca^n'na, the Unto, the 

 Pinna, the Strombus, and the Tiirbinella are simply 

 execrable. They are printed upon a fearful black ground 

 (one almost expects to see " Sacred to the memory of," 

 &c.), inclosed by a thin white line with ornamental 

 corners, and seem to us to have a most common appear- 

 ance. We cannot see one redeeming feature in them, the 

 drawing and colouring of the shells being equally bad. If 

 another edition is called for, fresh and accurate illustra- 

 tions should be provided. E. A. S. 



OUR BOOK SHELF 



The Definitions of Euclid, ivilh Explanations and 

 Exercises, and an -Appendix of Exercises on the First 

 Book. By R. Webb, M.A. Pp. 48. (Londoji : G. 

 Bell and Sons, i886.) 

 There are some good points in this little book which 

 will make it a useful help in many cases, especially with 

 backward and dull pupils. The explanations are clear 

 and precise ; the exercises are very simple, and aim 

 chiefly at insuring that the pupil really masters the idea 

 involved in the definition illustrated ; and good diagrams 

 are supplied. We are sceptical, however, as to the 

 advisability of representing " each of two or more lines 

 which are parallel to one another by two straight lines 

 close together." This is put forward as an assistance to 

 the memory, but the assistance, such as it is, may be very 

 dearly purchased. 



The deductions at the end of the volume — three or four 

 on each proposition of Euclid, Book I. — are nearly all 

 very easy ; they do not require any knowledge of 

 propositions subsequent to the ones to which they are 

 attached. 



Berdttelse om en Resa til Cr on land. (" Narrative of an 

 Expedition to Greenland.") By Nils O. Hoist. (Stock- 

 holm : Norstedt und Sbner, 1SS6.) V 



Dr. Holst's object in visiting Greenland was to inves- 

 tigate the phenomena of glacial action as they are 

 manifested in the varied geological formations of the 

 Arctic regions, and to secure materials which might help 

 to elucidate many of the questions still needing solution J 

 in regard to the Ice Age in Europe. I 



Having obtained permission from the Swedish King to | 

 absent himself from his labours in connection with the 

 Swedish Geological Surveys, and having been allowed by 

 the Royal Danish Greenland Trading Company — generally 

 very chary of granting similar favours — to make the voyage 

 in one of their ships, he embarked at Copenhagen on 

 April 8, 1881, in the Peru, which after thirty-nine days 

 sighted the west coast of Greenland. Here he found 

 himself suddenly brought into immediate contact with 

 the ice-formations which he had come so far to study, 

 for the pack-ice, which is annually brought by the Arctic 

 current to the coasts of Greenland between the months 

 of March and September, was so unusually dense in that 

 year that it required ten days' cautious navigation to 

 penetrate the ice — which, with a depth of 10 feet and 

 more, was in many parts from 8 to 10 miles in width — 

 and to reach safe anchoring-ground. This was at length 

 found at Smalle, in 61° 32' N. lat., far to the north-west of 

 Julianehab, for which the Peru was bound, and there 

 Dr. Hoist left the ship and engaged a native boat to 

 carry him to the mouth of Arsukfjord, and to the settle- 

 ment of Tigssaluk, where he had the opportunity of 

 examining several of the " horse-shoe " moraines described 

 by Hornerup, and comparing the land and water ice- 

 sheets with their respective crevasses, glaciers, packs, and 

 floes, besides making as complete a geological survey of 

 the coast which he visited as time and circumstances 

 permitted. In the course of these expeditions he ascended 

 several of the characteristic so-called " nuiiataelcor," 

 or bare fjeld-tops, some of which are between 3000 and 

 4000 feet in height. On these isolited hill-tops were 

 found, amongst other plants, various Cladonias, Silenes, 

 Cetrarias, and Luzulas, besides Rlwdodendron lapponicuni, 

 Ncphronm arcticuni, &c. 



Dr. Hoist was disappointed in his expectation of ex- 

 amining the kryolite mines of Ivigtut, orders having been 

 received from headquarters in Copenhagen that strangers 

 should not be allowed to see the works, but he was able 

 to determine the geological character of the district, 

 and the conditions under which the mineral is found. 

 According to him, the predominant rock is a grey, finely- 



