848 



44. 



Nernst & Lercli, 



45. 



Niven, 



46. 



Palmer, 



47. 

 48. 



n 



Ratz, 



49. 



Rosa, 



50. 

 61. 



Rukop, 

 Smale, 



52. 

 53. 

 54. 



>> 

 Speyers, 

 Tang!, 



55. 



Terescliin, 



56. 



Thomson, 





Nernst, 



57. 



Thomas, 



58. 



Thwing, 



59. 



Turner, 



60. 



Walden. 



61. 



Wildermuthj 



62. 



Yule, 



Mr. H. Carrinoton on the 



o 



Ann. PhTs. xy. p. 836 (1904). 



Proc. Koy. Soc. (A) Ixxxv. p. 139 (1911). 



Phys. Rev. xiv. p. 38 (1902). 



„ ., xvi. p. 267 (1903). 

 Ztschr. Phys. Chem. xix. p. 94 (1896). 

 Phil. Hag. xxxi. p. 188 (1891). 

 Ann. Phys. xlii. p. 489 (1913). 

 Wied. Ann. lvii. p. 2] 5 (1896). 



„ lx. p. 625 (1897). 

 Sill. Ainer. Journ. xvi. p. 61 (1903). 

 Ann. Phvs. x. p. 748 (1903). 

 Wied. Anu. xxxvi. p. 792 (1889). 

 Phil. Mag. xxxvi. p. 320 (1893). 

 Ztschr. Phvs. Chem. xiii. p. 530 (1894). 

 Phvs. Rev!' xxxi. p. 278 (1910). 



„ „ ii. p. 35 (1895). 

 Ztschr. Phvs. Chem. xiv. p. 286 (1894) 



„ „ xxxv. p. 385 (1900). 



Bull. Acad. St. Petersb. vi. pp. 305, 1055 



(1912). 

 Ann. Phvs. viii. p. 212 (1902). 

 Wied. Ann. 1. p. 742 (1893). 

 Phil. Mag. xxxvi. p. 531 (1893). 



LXXX. The Moduli of Rigidity for Spruce. 

 By H. Cabrdjgton, B.Sc, M.Sc.Tech., A.M.LMech.E* 



[Plate IX.] 



THE investigation described below was conducted during 

 the war in the College of Technology, Manchester, 

 for the Air Board and the Royal Aircraft Establishment. 

 Aeroplane designers found themselves at some disadvantage, 

 owing to the lack of information about the elastic properties 

 of timber, and so far as the writer is aware, no published 

 records of values of the moduli of rigidity, determined on 

 the assumption that the wood had three planes of elastic 

 symmetry, were then available. Torsion experiments on 

 prisms of wood were conducted by Gerstner t (1833) and 

 Pacinotti & Peri J (1845), who used the old Coulomb theory 

 that plane sections remained plane during strain to calculate 

 the values. A short table of values of Young's Modulus 

 along the grain, Poisson's Ratio, and the Modulus of 

 Rigidity for beech and pine, based on the experiment 1 

 results of Chevandier &AYertheim § (1848) and of Mallock || 



* Communicated by the Author. 



t ' The Theory of Elasticity,' Todhunter & Pearson, vol. i. art. 810. 



\ Ibid vol. i. arts. 1250-1252. 



§ Ibid. vol. i. arts. 1312-1314. 



|| Proc. Koy. !Soc. Lond. vol. xxix. pp. 157-161. 



