178 



NATURE 



[December 26, 1895 



brilliancy was such that it lit up the dark road (a lane with 

 a high hedge) as though by a flash of lightning, or like a 

 bright moonlight night. I turned and saw the meteor, almost 

 due north from me, flash through about 5° of the sky, then 

 separate into three distinct portions, of the following relative 



"'«'■'>' (f.^*)' 



and then vanish. 



We learn from the British Medical Journal that the Govern- 

 ment of India have approved of a Committee, to assemble in 

 Calcutta in January next, to revise the present cholera rules for 

 the Forces, of which Mr. Hart spoke as inadequate and discredit- 

 able. The Committee will be composed of the Quartermaster- 

 General in India, the Principal Medical Officers H.M. Forces 

 in India, and the Sanitary Commissioner with the Government, 

 associated with Mr. Hankin, the bacteriologist. 



It is proposed to form a society to bring together more closely 

 those who have taken up Reptiles as their hobby, and it is hoped 

 that by this means interest may be kept up and mutual help 

 secured by all concerned. Dr. Arthur Stradling has consented 

 to become President. In order that a working basis may be 

 secured at once, those who intend to become members should 

 communicate with the Secretary, Rand Rectory, Wragby, 

 Lincolnshire. 



On Friday last, several members of the British Chamber of 

 Commerce, which has for some years advocated in the interest 

 of English trade the adoption of the metric system in England, 

 visited the boys' and girls' elementary schools of the Tenth 

 Arrondissement at Paris, and listened to a lesson on the system, 

 with the idea of seeing the ease with which it is taught and the 

 efficiency attained. On Saturday, the members were received 

 officially by the Paris Municipal Council, the President of which 

 referred to the prospect that the metric system would be an 

 additional link of fellowship between the two nations. 



The Annual Progress Report of the Geological Survey of 

 Queensland is chiefly interesting from the account it contains of 

 Mr. Jack's investigations into the artesian water supply of that 

 country. A paper on the subject was read to the Australian 

 Association nearly a year ago, so that the general results are not 

 new. It seems probable that all the water obtained by sinking 

 into the " Blythesdale Braystone " and other porous beds of the 

 Lower Cretaceous is only an insignificant part of the total 

 amount which must otherwise drain off into the sea, so that the 

 amount of water obtained is capable of indefinite increase. 

 There is a statistical appendix on the various artesian wells ; 

 and many matters of local geology are also dealt with in the 

 report. 



The possibility that the ores and other vein minerals have 

 been segregated in the veins out of the minute quantities diff'used 

 through the country-rock they traverse is so suggestive a one, 

 that great interest attaches to any discovery that may throw 

 light on this question. In New South Wales, auriferous granite 

 has been known and worked for several years past in the 

 Timbarra district. The rocks of this gold-field have recently 

 been described by Mr. G. W. Card {Records Geol. Survey New 

 South Wales, vol. iv. pt. iv. p. 154), who has found gold and 

 silver in both the granite itself, which is a binary granite, and in 

 eurite-veins which cut it. Moreover, small auriferous quartz- 

 veins cut the granite. The exact mode of occurrence of the gold 

 in the igneous rocks does not seem to have been made out. 



The diamond fields of Bingara, New South Wales, have been 

 examined and reported on by Mr. G. A. Stonier, of the Govern- 

 ment Geological Survey, with the view of ascertaining whether 

 or not they resemble the deposits at Kimberley, in South Africa. 

 It has been decided that no such resemblance can be made out, 

 NO. 1365, VOL 53] 



but no new light has been thrown on the genesis of the diamond. 

 At Bingara, the diamonds are found in alluvial drifts of Tertiary 

 age, in which pebbles of jasper, much waterworn, predominate, 

 and nothing resembling the picrite- porphyry of Kimberley is^ 

 found in the neighbourhood. It has long been held that the 

 diamonds at Bingara were formed in situ in the drifts, but this- 

 view is not supported by Mr. Stonier. He suggests that the 

 source of the diamonds is an intrusive mass of serpentine (an 

 altered peridotite), which has metamorphosed the carboniferous 

 rocks in the vicinity, producing great quantities of jasper, and of 

 this, as already stated, the diamantiferous gravels are chiefly 

 formed. The diamonds themselves are of superior quality to> 

 most of those found at Kimberley ; but, being somewhat harder, 

 take longer to polish. The largest stone found hitherto was 

 only 2| carats in weight when rough, and not quite \ carat after 

 it had been cut. 



A recent number of the Coinptes rendus (December 2, 1895,. 

 contains an account of a determination of the ratio v of the 

 electrostatic and the electromagnetic units made by M. D. 

 Hurmuzescu. The author has employed a method, first usecB 

 by Maxwell, in which an electrostatic attraction is balanced by 

 the repulsion between two circuits carrying a current. The 

 electrostatic difference of potential at the ends of a known re- 

 sistance R traversed by a current is obtained by an absolute- 

 electrometer with a cylindrical movable electrode. The current 

 which passes through the resistance R also passes through ark 

 electro-dynamometer, the movable coil of which is rigidly at- 

 tached to the lever carrying the attracted cylinder of the electro- 

 meter. This electro-dynamometer consists of a long solenoid 

 with a single layer of wire, and of a small movable coil placed at 

 the centre of this solenoid, and inclined at 90° to the axis of the 

 solenoid. The value of the resistance R, for which the turning 

 couples due to the electrometer and dynamometer are exactly- 

 equal, is found, and from the geometrical constants of the in- 

 strument the value of v can be calculated. The author considers 

 that the length measurements, &c., are correct to i in 3000, 

 and that the accuracy of the value of v is limited by the ac- 

 curacy with which the ohm is known. The results obtained give 

 values for z* being between 3 "ooos x 10"* and 3 •0020 x 10^". 



A new heavy liquid has been discovered. Mr. S. L. PenfiekJ 

 describes its preparation in the December number of the 

 American Journal of Science. Mix equal proportions of the 

 nitrate of silver and thallium, and on heating the mixture it fuses- 

 at 75° C. , forming a clear mobile liquid of density 4-5, which 

 mixes with water in all proportions. It can therefore be used 

 to separate mineral particles of densities below 4"5. When still 

 heavier particles have to be separated, the proportion of thallium, 

 may be increased. When the ratio is 3 : 4 the mixture fuses 

 below 100° C. and has a density of about 47. At 2:4 the 

 fusing point becomes 150° C, and the density 4*8 ; at I 14 it is 

 about 4 '9, and fusion only takes place at 200". Finally, when 

 pure thallium nitrate is used, the point of fusion is 250" C, and 

 the density closely approaches 5. This high range of densities, 

 together with the fact that the salts do not attack many minerals,, 

 make the liquid especially valuable for mineralogical purposes. 

 A convenient separator is described by the same author. It 

 consists of a thimble-shaped cup into which a wide tube is made 

 to fit. The tube can be closed at the bottom by a hollow plug. 

 This plug being removed, the heavy liquid is poured through the 

 tube into the thimble, and the minerals are thrown in and 

 stirred. The heavy particles sink into the thimble, and may be 

 removed by clo.sing the tube with the plug, and withdrawing the 

 thimble. The latter is then replaced, and the operation repeated! 

 with dilute liquid. With some practice an elaborate separation, 

 by densities is rapidly and easily accomplishfed. 



