286 



NA TURE 



iJan. 17, 1889 



diver the Gapu usually shifts its position from the carapace to 

 the plastron of the turtle. At the end of the day's fishing the 

 Gapu is eaten. The natives have a great respect for the Gapu, 

 and firmly believe the fish possesses supernatural powers. For 

 example, when there is something the matter with the bow of the 

 canoe, the Gapu is said to attach itself to the neck or the nuchal 

 plate of the turtle ; when the lashings of the outrigger to the 

 thwart poles are insecure, the Gapu is believed not to stick fast 

 to the turtle, but to continually shift its position ; if the 

 strengthening ties in the centre of the hold of the canoe are 

 faulty, the Gapu is stated to attach itself to the turtle and then 

 immediately to swim away. More than once 1 was told, " Gapu 

 savvy all the same as man ; I think him half devil." The sucker- 

 fish is not used to haul in the large green turtle. I was re- 

 peatedly told that it would be pulled off, as the turtle was too 

 heavy. The above information was gathered from several 

 sources, and checked by means of much questioning. 



Amphioxus. — A species of Amphioxus, apparently very 

 similar to A. lanceolatus, was not uncommon at one spot at 

 Mabuiag, at a depth of from 3 to 4 fathoms. A species of 

 this animal is catalogued as follows by Mr. Krefft, in his list of 

 " Australian Vertebrata, Fossil and Recent " : " Branchiostoma 

 lanceolatum. Dredged in Bass's Straits, by H.M.S. Herald, at 

 a depth of from 10 to 12 fathoms." I am not aware whether it 

 has been found elsewhere in Australian waters. 



Alfred C. Haddon. 



Thursday Island, November 12, 1888. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE. 



Cambridge. — The Sedgwick triennial prize has been awarded 

 to Mr. Alfred Harker, Fellow of St. John's College. The sub- 

 ject of the essay is " 'J'he Petrology of the Igneous Rocks 

 associated with the Cambrian (Sedgwick) of Carnarvonshire." 



SCIENTIFIC SERIALS. 



In the number of iheyoitrnal of Botany for December 1888, 

 Mr. S. Le M. Moore has an interesting article on photolysis 

 in Lemna trisulca, in which he contests some of Stahl's con- 

 clusions as to the effect of day and night 011 the relative posi- 

 tions of the chlorophyll-grains on the cell-walls. The remaining 

 articles, both in this number and in that for January 1889, are 

 chiefly of interest to geographical or systematic botanists. 

 Messrs. Britten and Boulger's " Biographical Index of British 

 and Irish Botanists " has now advanced as far as the letter G. 



In the Botanical Gazette for November 1888, Miss E. L. 

 Gregory completes her account of the development of cork- 

 wings on certain trees, the trees described in the present 

 instalment being species of Acer and LiquiJambar. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, November 22, 1888. — "Report of Re- 

 searches on Silicon Compounds and their Derivatives. Part 

 I." By J. Emerson Reynolds, M.D., F.R.S., Professor of 

 Chemistry, University of Dublin. 



The present investigation was undertaken some years ago 

 with a view to examine the action of the silicon haloids — but 

 more especially of silicon tetrabromide — on various compounds 

 containing nitrogen, as our knowledge of the relations of silicon 

 and nitrogen is extremely limited. 



It was ascertained at an early stage of the inquiry that the 

 bromide of silicon is much superior to the chloride as a reagent 

 with nitrogenized compounds, but since the bromide had appar- 

 ently not been obtained in any quantity even by its discoverer, 

 Serullas, considerable time had to be devoted to working out a 

 method for the production of a sufficiently large supply of this 

 material. The method adopted is described in the full paper. 



In the purification of the crude tetrabromide a new chloro- 



bromide^ of silicon was aiscovered, which boils at 141° C. This 

 proved to be the compound SiClBr,, which was required to. 

 complete the series of possible chlorobromides of silicon. 



The first group of nitrogen compounds subjected to the action 

 of silicon tetrabromide included the primary thiocarbamide or 

 sulphur urea, obtained by the author in 1869, and the allyl-, 

 phenyl-, and diphenyl-thiocarbamides. 



All these are shown to unite with silicon tetrabromide, and 

 afford the highly condensed compounds — 



(H4N,CS)8SiBr4, 

 (C.,H5",H3N2CS)8SiBr4, 

 (CfiH„H.^N,CS)8SiBr4. 

 ((C6H3)2H3N„CS)8SiBr4. 



These are more or less vitreous solids, with the exception of 

 the allylic compound, which is a transparent and singularly 

 viscous liquid. All are dissolved and decomposed by water and 

 by alcohol. 



The action of alcohol on the compound (H4N2CS)8SiBr4 was 

 studied in detail, and it was shown that not only do ethyl 

 bromide, thiocyanate, and diethylic silicate result, but that the 

 representatives of two new classes of thiocarbamide derivatives 

 are formed. 



The first of these is a beautiful tetrathiocarbamide compound 

 whose formula proved to be — 



(H5N,CS)4NBr, 



which may obviously be written — 



(H4N.,CS)4H4NBr. 



This body separates from alcohol in fine masses of crystals 

 resembling sea anemones in appearance, which melt at 173°- 

 174°, and begin to decompose at i78°-i8o°. The synthesis of 

 this substance was effected by heating ammonium bromide with 

 thiocarbamide. 



Several homologues of the above tetrathiocarbamidammonium 

 bromide were produced by synthetic methods ; some of these 

 contain chlorine or iodine instead of bromine. The following 

 are examples of the compounds found in the course of this part 

 of the investigation : — 



(H4N.,CS)4H4NBr, 



(H4N2CS)4H4NCI, 



(H4N2CS)4H4NI, 



(H4N2CS)4(Cn3)H3NBr, 



(H4N2CS)4(C2H5)2H,NBr, 



(H4N2CS)4(C2H3)3HNC1. 



By the action of silver nitrate on the tetrathiocarbamidam- 

 I monium bromide the crystalline dithiocarbainide compound with 

 silver bromide was obtained — 



(H4N2CS)oAgBr. 



This was subsequently produced by the direct union of thiocar 

 bamide with the pure silver haloid. The compound — 



(H4N,CS)2AgCl 

 fine crystals, a 



were other similar 



was also obtained 

 substances. 



A trithiocarbamide compound is also formed during the 

 action of ethyl alcohol on (H4N2CS)gSiBr4, but it is much more 

 soluble than that which first separates. It is also crystalline, 

 and its analysis and reactions lead to the formula — 



(HgNoCS)3Br,C2n3Br. 



Hitherto only mono- and di-thiocarbamide derivatives have 

 been known, but the results above stated in outline prove that 

 tri- and tetra-thiocarbamide compounds are formed in presence 

 of silicon tetrabromide and certain other agents, which latter 

 form addition products with the condensed amide. * 



So far, cases were only dealt with in which silicon tetra- 

 bromide combined with nitrogenized groups without loss of it* 

 halogen. The next stage of the inquiry involved the investiga- 

 tion of certain interactions in which the tetrabromide loses rt/^ 

 its halogen. One of the chief results obtained in that direction 

 forms the subject of a separate communication. 



' The chlorine required for the production of this compound was derived 

 from the crude bromine (which always conains chloride of bromine) used in 

 preparing the tetrabromide. 



