3^4 



NA TURE 



[February i6, 1905 



Malayan Peninsula," has, after a study of several 

 years' introduced a new arrangement with two main 

 sections, Sissoa, which includes the greater part of 

 Bentham's Triptolomea and Sissoa, and Amenmnon, 

 called after an American type. Dr. Prain's cl.issifi- 

 cation differs from Bentham's, since he adopts the 

 shape and orientation of the corolla and the form of 

 the style as the criteria of his subdivisions instead of 

 I he characters of the inflorescence, stamens, and fruit. 

 The genus is distributed through the tropics of 

 .Vfrica and .\merica as well as Asia, and it seems 

 a pity that the author did not see his way to extend 

 his monograph to all the known species. The dis- 

 tribution in Asia is considered for five provinces. 

 East China, Indo-China, Indo-Himalaya, Malaya, 

 and Papuasia; the number of endemic species in each 

 is large, and amounts to 72 per cent, for East China. 

 Very "few species are found in more than two of 

 these provinces ; Dalbergia tamarindifolia occurs in 

 four, and Dalbergia torta ( = D. monosperma). which 

 has pods well suited for dispersal by ocean currents, 

 is the onlv species found in all five provinces. Owing 

 to the inclusion of recent specimens from Malay and 

 China, the total number of authenticated species 

 amounts to eightv-si.x ; a few, including the Dalbergia 

 laceifera of Lanessan, still remain unidentified. The 

 memoir is illustrated with diagrams of groupings 

 and maps of distribution, as well as with figures of 

 each species, and issued as the first part of the tenth 

 volume it forms a valuable addition to the Annals 

 of the Royal Botanic Gardens, Calcutta. 

 The Process Year Book. Penrose's Pictorial 

 Annual, 1904-5. Edited by William Gamble. 

 Pp. .xvi+160. (London: Penrose and Co.) 

 Every year we receive this annual, and each time 

 it is our pleasure to point out the very high standard 

 which the volume attains. The current issue bids us to 

 repeat the opinions expressed in our previous notices, 

 and to supplement them with the statement that the 

 standard has again been changed to one of a higher 

 order. 



To gain some idea of the possibilities of process 

 work of to-day, when the best work and materials 

 are employed, the reader has only to take up this 

 book and 'examine the contents, which will at once 

 indicate the high state of efficiency and the variety 

 of methods that are available. In the first place we 

 have a series of instructive articles, covering 160 

 pages, most of which are from the pens of well-known 

 workers. These deal with manifold portions of a 

 far-reaching subject, and give the advice, results of 

 experience, and views of these workers on numerous 

 points of interest. Of the illustrations, which form 

 such a conspicuous feature of this annual, much could 

 be written, for it is in them that we see the practical 

 results of the processes in use to-day. If we sum 

 up the plates, colour prints, suppleme'nt illustrations, 

 and illustrations in the text, we have a collection 

 which for varietv of subjects and excellence of repro- 

 duction is unique. The photogravure, as a frontis- 

 piece bv J. J. Waddington, Ltd., the "Turner" 

 reproduced bv the three-colour process of .Andre and 

 Sleigh, and the interlayed half-tone by the .\rthur 

 Cox Illustrating Co., Ltd., are three amongst a host 

 of other good samples that are met with. 



.Apart from the large number of process workers 

 who await annually the appearance of this year book, 

 this handsome volume will appeal to a wide circle of 

 readers who are in any way connected with the 

 artistic or utilitarian side of the art of reproducing 

 pictures. The editor and his contributors, together 

 with the publishers and printers, all deserve great 

 credit for such an admirable result of their combined 

 efTorts. 



NO. 1842, VOL. 71] 



LETTERS TO THE EDITOR. 

 [The Editor does not hold himself responsible for opinions 

 expressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, yejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications.] 



On a Method of Using the Tow-net as an Opening 

 and Globing Tow-net. 



Every naturalist who has engaged in marine research 

 is aware of the great difficulties which attend upon research 

 in the intermediate depths. 



Great ingenuity has been displayed in the invention of 

 very elaborate instruments— many of them hopeful, some 

 of them successful. It had appeared to me, as the result 

 of observations, and after conversation with Mr. J. \. 

 Buchanan, who had made similar observations, that a solu- 

 tion of this problem might be found easily in experiments 

 with the ordinary tow-net. 



Our joint exp'erience was this. If an ordinary tow-net 

 were lashed at two opposite points of the rim to a rigid 

 sounding-wire, and so plunged at speed into the depths, 

 the net would fold over and close. It might then be towed 

 at the required depth and afterwards reeled in by the 

 sounding engine at express speed— again closing in its 

 upward course. 



Through the great kindness and sympathy of Mr. M. H. 

 Gray, of the Silvertown Submarine Telegraph Company. I 

 was' afforded an opportunity of putting this theory to the 

 test on board the Dacia. 



The conditions of the experiment appeared to me at the 

 time adverse, since mv tow-nets and other apparatus were 

 missing at Gibraltar ;' but this was a blessing in disguise. 

 I set to work and made a tow-net out of old bunting and 

 the rim out of a barrel hoop. This tow-net was so flimsy 

 that in towing it alongside at little more than mere 

 steerage-way it frequently burst. To plunge it into the 

 depths would be a supreme test, since not even No. 20 

 Miller's Silk in an open net could stand the strain I 

 proposed. Off the north-west coast of Africa I had three 

 days' opportunity of experiments, the absurd tow-net being 

 in ludicrous inverse proportion to the magnificent sounding 

 crew and sounding engine. .\ reference to the diagram 

 will show A, the descent of the net folded over ; n. the 

 net opening at the required depth ; c, the net being towed 

 at the required depth : and i>, the net being reeled in 

 closed as in its descent. . , u j 



I confe.ss that when the first experiment w^as made 1 had 

 faint hope of seeing that flimsy tow-net again, but it 

 emerged with many organisms we had not captured on 

 the surface. To cut inattirs short, these experiments were 



