120 



SCIENCE. 



cause corresponding variations in the heat at the point of 

 contact of the needle with the cylinder, and this again pro- 

 duces a mechanical movement of the pressing point, as 

 well as of the air surrounding it, sufficient to give forth 

 sound-waves. If such be the case the effect should be dif- 

 ferent for different metals, those answering best which have 

 the lowest thermal conductivity and also the lowest specific 

 heat. That this is really so, is showing by substituting 

 cylinders ol other metals for the bismuth, all other things 

 remaining the same. In this way I have compared lead, 

 tin, iron, copper, carbon, and find that they all give forth 

 the simple loose contact sound when the cylinder is station- 

 ary, but that it is only with bismuth that there is any very 

 intensification of the sound when the cylinder is 

 rotated. Now, by consulting the appropriate tables I find 

 that bismuth is a fraction lower than any other common 

 metal in specific, while heal is much below them all, in 

 thermal conductivity. This seems to bear out my explana- 

 tion to a certain extent. 



Tick subject of a depraved taste in animals is an interest- 

 ing one, which has not been studied as much perhaps as it 

 might. In human beines it would seem to depend on ill- 

 health of cither body or mind, but in animals it would seem 

 as if it might be present and the animal enjoy good health. 

 One remarkable instance in an herbivorous animal we can 

 vouch for. It occurred in a sheep that had been shipped on 

 board one of the P. and O. steamers to help to supply the 

 kitchen on board, but while fattening it developed an inor- 

 dinate taste for tobacco, which it would eat in any quan- 

 tity that was given to it. It did not much care for i 

 and altogether objected to burnt ends ; but it would greed- 

 ily devour the halt-chewed quid of a sailor or a handful of 

 roll tobacco. While chewing there was apparently no un- 

 due tlow of saliva, and its taste was so peculiar that most 

 of th> board amused themselves by feeding 



it. to tec lor themselves il it were leallv so. As a conse- 

 quence, though in fair condition, the cook was afraid to 

 kill the sheep, believing that the mutton would have the 

 flavor ol tobacco. Another vcrv remarkable case has just 

 been communicat' >1 to us by Mi. Francis Goodlake: this 



time a Hesh-eatmg animal in the shape ol a kitten, about 

 five months old, who shows a passionate loudness lor sal- 

 It eats no end ol sliced i ucumbei dressed with rin- 



when hot with (avenue pepper Alter a little 



iten a piece ->t boiled beef with mustard. 

 Its ni eat i slit e <>i cucumber 



which had salt, on it. The kitten is 



rently in good health, and its , \tt ior linary taste is not 

 inted lor. I. ven supposing ,t once got I 

 why should it now select to | 

 the dressing to [hi 



MBS Ol i in Ii LBOB Mil. I 



.ins so liable to he Interfered with by what 



■ • iti< telegraph. Fish 



gnaw and molluski over weight the submarine conductor! 



oi ihr sui • while there is .u leas) one in- 



' ingling himself in a deep 



to us utter disorganization. It is stated that 



within the i , ive been aixrj 



s Interruptions to telegraphii communication in 



Summatra, by cli in one instance, the* sagacious 



lestroyed I i onsldi r- 

 ■ oi the in, .v.i\ the wires and insula- 



of all ml" s .in : 

 m ih u inasia, 



•n ill \ break Ins; them and carrying ofl the Insul 



while ihi i, and hull. does oil the l r .i< k 



• I the line a duU o! 



r< do wild animals to 



wire*, w! 



,11'iillv ' ut down b) ll 



.m It. .in tin in 



in ornament It has 



i. on in lh 



. >f won. when tin i 



■ i limbing i)m in with 



FHYSICAL NOTES. 



In an article of great length, extending through the last 

 three numbers of the Ammm/tn der Pkysik unJ ClUmie, which 

 exhibits extraordinary scope of research and ingenuity, the 

 learned Professor Quincke exhausts the subject of elec- 

 trical expansion. The following results are drawn from 

 his investigation : 



i. Solid and liquid bodies alter their volume when they 

 are acted upon, the same as Leyden jars, by electrical 

 forces. 



2. This change of volume is not the effect of heat, but is 

 mostly an expansion ; though it may also be a contraction, 

 as in the case of the fatty oils. 



;. No change of volume was observable in gases under 

 the action ol electrical forces. If such occurred it was 

 smaller than the original volume. 



4. There was an instantaneous change ol volume in Hint 

 ulass, but it took longer in German glass, which is a better 

 conductor of electricity. By discharge of the coatings of 

 spherical and tubular condensers, the glass resumes its 

 original volume. 



5. There is a simultaneous change of length and volume 

 in tubular condensers. 



6. The change of volume and length increases as the 

 difference of potential in the coatings, and inversely as the 

 thickness ol the insulating substance of the condensci ; 

 and they are nearly proportional to the square of strength 

 of potential and thick 1 



7. Under otherwise equal conditions the expansion in 

 volume and length differ according to the insulating sub- 

 stance of the condensi 1 . 



8. After the discharge ol the coatings ol the condensers, 



there is a residue, so to speak, ol this change <>l volume. 

 which is veiv small in the case ol Hint glass, but gicatci in 



German glass, and which seems to have some connection 

 with the electrical polarization of the mass of the glass 



itself. 



9. The change ol mass and volume does not result from 

 an electrical compression of the Insulating substance. 



10. In Hint glass electrical expansion takes place equally 



in all directions, as in the expansions produced by InCTI SW 



oi temperature, independent oi the charactei and direction 

 ot the eli ctrical forces. 



11. Electrical change oi length and volume take* place 

 in glass neatly in tin same waj with increase oi tempera- 

 ture, as the dialectric constants, or the electrical conduc- 



! the glass. 



12. Action of electrical forces diminish the elasticity ol 



Hint glass, German glass, and caoutchouc, but incrcasi 



that of 1111c. 1 and gulta pen ha. 



13. The electrical piercing ol glass and otbei substances 

 is .1 H suit of tin unequal < l< ctrical < (pension of the Insula* 

 toi in different pin es, 



11 Hv unequal electrical expansion solid and liquid 

 substances an- unequally dilated and become double re- 

 fracting, as othei timilai substances do when heated. 



15. (ilass, when equally expanded, shows no electrical 

 double refraction undei electrit al fon 



1' I h. 1, 1 .1 1 1 1 111 of Substances with positive and 111 



double refraction (to which 1 m Ken ftrsi called attention), 

 Is explained bj thewaj In which different substances change 



llii 11 i sponi ids of 11 li.u lion wild I lit i 1 di nsiiv and volume. 

 17. With a 1 oust. oil dilli leni e of potential in the 1 oating 



of a condenser, aftei long charging, the electrical force 

 Indifferent layers ol the insulative substanot at the 



•..inn time, 01 in the vuin plat C al different limes. 



M. lb i ihi 101 has recentli made .m apparatus foi 



iring the heat ol ibustton ol detonation, 



wbii b ilallj "i .» bomb suspend) d In •» ■ .don 



iin u r. 



Hi w 1 11 n, the mineral collector, has discovered 



in Burks County, \ < . a in w locality oi 1 urgusoniti 

 1 he mini 1.1 1 was chemically determined bj Dr. J, Lawreac) 

 Smith. 



