132 



Dr. Tyndall on Molecular Influences. 



Deflections. 



§ . 



1 American Birch... 



2 Oak 



3 Beech 



4 Cororaandel-wood 



5 Quebec Pine , 



6 Beef-wood 



7 Black Ebony , 



8 Bird's- Eye Maple 



9 Lance-wood 



10 Zebra-wood 



11 Box-wood 



12 Tamarind- wood.. 



13 Teak-wood , 



14 Rose-wood 



15 Mazatlan-wood .. 



16 Satin-wood 



17 Braziletto 



18 Locust-wood 



19 Ruby-wood 



20 Peruvian -wood ... 



21 King-wood 



22 Bladder-nut-wood 



23 Larch 



24 Princes-wood 



25 Green-heart 



26 Walnut 



27 Drooping Ash . . . 



ii. 



,13 ■ 



90 



9-5 



8-8 



9-8 



100 



100 



9-5 



110 



10-6 



8-2 



99 



111 



9-9 



10-4 



10-5 



11-9 



9-2 



100 



103 



10-7 



10-3 



100 



10-0 



111 



11-4 



110 



110 



III. 



ill 



*s! 



110 

 110 

 10-8 

 12-3 

 110 

 11-4 

 10-5 

 120 

 121 

 100 

 120 

 121 

 12-4 

 12-6 

 12-5 

 12-3 

 110 

 110 

 11-2 

 11-7 

 11-7 

 120 

 110 

 131 

 12-6 

 13-0 

 12-0 



II 



Botany Bay Oak 



29 Cocoa-wood 



30 Madagascar Red-wood 



31 Sandal-wood . 



32 Tulip-wood 



33 Camphor- wood 



34 Olive-tree 



35 GaffleDeal 



36 Ash 



37 Green Ebony 



38 Black Oak 



39 Apple-tree 



40 Cam-wood 



41 Iron-wood 



42 Chestnut 



43 Sycamore 



44 Spruce Fir 



45 Honduras Mahogany.. 



46 Brazil-wood 



47 Yew 



48 Elm 



49 Plane-tree 



50 Portugal Laurel 



51 Bullet-wood 



52 Spanish Mahogany .. 



53 Scotch Fir 



54 Laurel ,. 



9-9 

 11-9 



10-7 

 100 

 11-0 



8-6 

 10-5 

 100 



9-5 

 10-5 



8-0 

 100 

 13-4 

 10-2 

 101 

 10-6 

 11-8 



90 

 11-9 

 11-0 

 100 

 100 

 100 

 100 

 11-5 

 100 

 120 



in. 



III 



HI 



12-4 

 13-6 

 11-3 

 11-7 

 121 

 100 

 13-2 

 110 

 11-5 

 12- 

 9-4 

 12-5 

 150 

 12-4 

 11-5 

 12-2 

 12-5 

 100 

 13-9 

 120 

 11-5 

 120 

 11-5 

 11*7 

 12-5 

 120 

 150 



The above table furnishes us with the fullest corroboration of 

 the result arrived at by De la Rive and DeCandolle, regarding 

 the superior conductivity of the wood in the direction of the fibre. 

 Evidence is also afforded as to how little mere density affects the 

 velocity of transmission. There appears to be neither law nor 

 general rule here. American Birch, a comparatively light wood, 

 possesses undoubtedly a higher transmissive power than any 

 other in the list — a result which has been established by nume- 

 rous experiments, although but one appears cited in the table. 

 Iron-wood, on the contrary, with a specific gravity of 1*426, 

 stands low. Again, Oak and Coromandel-wood, — the latter so 

 hard and dense that it is used for sharp war instruments by 

 savage tribes, — stand near the head of the list, while Scotch Fir 

 and other light wood stand low. 



