May 2 2, 1879] 



NATURE 



17 



Note on the lodobromite of A.' v. Lasaulx 



In the Jahresherichte fiir Minerahgie for 1878 A. v. Lasaulx 

 has described a new tilver haloid mineral, having the composi- 

 tion Aff^Brj, Ag„CU, Agl, or AgjCUBrjI, which he cites as the 

 first instance of the three haloids occurring crystallised together 

 in nature. Several chloro-bromides of silver have been found in 

 Chili in the silver mines of Chaiiarcillo, and, according to Dana, 

 an iodobromide has also been detected. The present mineral, 

 which should be called chlorobromiodide, was found associated 

 with beaudantite in a mine in the district of Ems, Nassau, in the 

 form of small yellow or olive green octohedrons never exceeding 

 3 mm. in size. The crystals are very malleable, and can be 

 pressed flat with the blade of a knife, and they possess a good 

 deal of lustre. On analysis they were found to contain : — 



Silver 59-96 



Iodine I5'°S 



Bromine I7'30 



Chlorine 7'09 



99-40 



In 1876 I prepared some of this substance artificially by fusing 

 together the chloride, iodide, and bromide in the proportions of 

 Agl 26'i692, AgBr 4r87o8, AgCl 31 •9600, which gives an 

 ultimate composition of : — 



Silver 6o*i336 



Iodine I4'I43S 



Bromine I7'8i76 



Chlorine 7'9o53 



The substance was prepared with other chlorobromiodides of 

 silver in order to see the extent to which iodide of silver (which 

 contracts considerably when heated from 142° to I45'5° C.) 

 modifies the coefficient of expansion of the chloride and brojnide, 



I which do not present similar anomalies. The results obtained 



I are given in the Free, of the Royal Society, vol. xxv. p. 294, 1877, 

 " On the Effects of Heat on some Chlorobromiodides of Silver," 

 and they are of additional interest now that the substance has 

 been found in nature. 



The compound artificially prepared is a brittle yellowish-brown 

 solid, giving a bright primrose-yellow powder, which turns 



' green on exposure to light. (It is noticeable that some of the 

 crystals found by Lasaulx were yellow, others green.) It is a 

 crystalline solid which emits loud hai'sh noises while cooling from 



' the molten condition. The fusing point is 330° C. The sp. gr. 



i 6' 1 52 when cooled quickly, but when fused and allowed to cool 

 slowly in hot paraffine, the sp. gr. fell to 6'o66. A. v. Lasaulx 

 makes the sp. gr. of the mineral as low as S'7I3. The artificially 

 prepared compound was found to possess a coefficient of cubical 

 expansion for 1° C. = 000012216 between 0° C. and I25"5. 



, Between I25"5 and I3i'5 it underwent slight contraction, while 

 between 131 "S and the fusing point the coefficient was O'oooi 5882. 

 It possesses two points of similar density, the one at I3i'5° C, 

 the otlier at or about 123° C. The volumes calculated from the 

 coefficients, taking volume at 0° C. as unity, were found to be : — 



Volume at 0° C. = i "000000 

 „ las's" = 1-015331 



131-5" = 1-015037 

 „ 330" = I -046666 (solid) 



„ 330° = I -104050 (liquid) 



75°° = I "177979 

 It is presumable that the other artificially-prepared chloro- 

 bromiodides described in the paper cited above will also be found 

 ill -ilver mines. G. F. RoDWELL 



Inherited Memory 



Having had my attention called, of late, to the subject of the 

 mit;ration of birds, I have of course been interested in the dis- 

 cussion between Dr. Weismann and Prof. Newton, and I cannot 

 help fancying that I have hit on the "missing link " which con- 

 nects the theory of the former with the facts of the latter. 



Are there not scientific men (and is not Dr. Carpenter one of 

 them) who consider that when we say an event has made " such 

 an impression on us that we shall never forget it " — we are not 

 merely using a metaphor, but stating a fact ? Now if something 

 analogous to "making an impression" on the brain really takes 

 place whenever we commit anything to memory — is it not possible 



that if the impression be deeply fixed, the impressed brain may 

 be transmitted by the parent to the offspring, who thus " inherits" 

 its ancestor's memory ? 



When we remember that birds take the same journey year 

 after year, generation after generation, century after century, 

 nay, even for ages after ages, I think we shall feel that there are 

 more marvellous things in nature than what I am asking you to 

 consider, namely, the possibility that the young bird at last 

 inherits a knowledge of the way, and is capable of performing 

 the journey alone. 



If " inherited memory" be accepted as a fact, what a flood of 

 light is thrown on many puzzles which have hitherto been classed 

 as " instincts" ; such as the building of birds' nests ; the point- 

 ing of pointer puppies, the knowledge possessed by young aniirals 

 of right and wrong food, and of friends and enemies ; I am not 

 sure that it will not even throw light on some mysteries in human 

 nature. When I was a child I had a dread of wolves (a very 

 common thing with children), and I find the dread reproduced 

 in one of my own children. Yet wolves have been so long 

 extinct in England that we should probably have to go back 

 many generations before we met with the nurses who quieted 

 crying children by threatening to give them to the wolves. May 

 not this be a case of " inherited memory ? " A. B. 



Intellect in Brutes 



Some years ago the late Hon. Marmaduke Maxwell, of 

 Terregles, took me to his stable to show me a cat which was 

 at the time, bringing up a family of young rats. The cat 

 some weeks previously had a litter of five kittens, three were 

 taken away and destroyed shortly after their birth ; next day it 

 was found that the cat had replaced her lost kittens by three 

 young rats which she nursed with the two remaining kittens ; a 

 few days afterwards the two kittens were taken away, and the 

 cat very shortly replaced them by two more young rats, and at 

 the time I saw them, the young rats — which were confined in an 

 empty stall — were running about quite briskly, and about one- 

 third grown. The cat happened to be out when we went into 

 the stable, but came in before we left ; she immediately jumped 

 over the board into the stall, and lay dow n ; her strange foster- 

 family at once ran under her and commenced sucking. What 

 renders the circumstance more extraordinary is, that the cat was 

 kept in the stable as a particularly good ratter. 



Cargen, Dumfries, May 9 P. Dudgeon 



Phosphorescence 



In regard to the effect of heat on phosphorescence, your 

 correspondent in last week's number will find that almost similar 

 phenomena have been observed by Dr. Draper, who treats of 

 the whole subject very fully and satisfactorily in his " Scientific 

 Memoirs." G. S. Thomson 



Clifton, May 18 



AN INDUCTION-CURRENTS BALANCE ' 



IMMEDLA.TELY upon the announcement of Arago's 

 discovery of the influence of rotating plates of metal 

 upon a magnetic needle (1824), and Faraday's important 

 discovery of voltaic and magneto-induction (1831), it 

 became evident that the induced currents, circulating in 

 a metallic mass, might be so acted upon either by voltaic 

 or induced currents as to bring some new light to bear on 

 the molecular construction of metallic bodies. 



The question was particularly studied by Babbage, Sir 

 John Herschel, and by M. Dovd,'^ who constructed an 

 induction balance, wherein two separate induction coils, 

 each having its primary and secondary coils, were joined 

 together in such a manner that the induced current in 

 one coil was made to neutralise the induced current in 

 the opposite coil, thus forming an induction balance, to 

 which he gave the name of differential inductor. In 

 those days physicists did not possess the exquisitely sen- 

 sitive galvanometers and other means of research that we 

 possess to-day, but sufficiently important results were 



' " On an Induction-Currents Balance, and Experimental Researches 

 made therewith." By Prof. D. E. Hughes. Read at the Royal Society, 



May 15. /T 1 o \ 



• D= la Rlv-, " Treatise on Electricity," vol. i. chap. v. (London, 1853) 



