Lastly, the iiuthor's own experiments, made at the Watertown Arsenal for the Boston Mauu- 

 factun-rs' Mutual Fire Insurance <;'ouii)auy, on tlie columnar strength of "yellow i)ine" aiul wliite 

 oak, 12 feet long and C to 10 indies thick, are brought in sujiport of tlie claim that such tests show- 

 less tlian half the unit strenglh of those on small pieces; data as to density, moisture, or life his- 

 tory of the specimens are everywhere la(-king. 



R. H. Thurston, Materials of Engineering, 1882, contains, perhajjs, more than any other 

 American work on tlie subject, devoling. in Chapters ii and in. 117 jiages to timber and its 

 strength, and in thecliai)ter on I'^uel several pages to wood and ciiarcoal and the products of 

 distillation. It also gives a description of some twenty five kinds of American and of a few 

 foreign timber trees, witli a (lescri[)tion of tlie structure and their wood in general; directions for 

 felling and seasoning; discusses briclly shrinkage, eiiaractei'istics of good timber, tiie inliucncc of 

 soil and climate on trees and their wood, and of the various forms of d(^eay of timber, methods of 

 preservation and adai)tation of various woods for vai'ious uses, nuu-h in the same maniuT as Kan- 

 kiue's Manual of Civil Engineering, from which many conclusions are adopted. The author refers, 

 besides foreign authorities, to the following American investigations: 



Gr. H. Corliss (uni)ublished?) is quoted as claiming thiit proi)ci' seasoning of hickory wood 

 increases its strength by 15 per cent. 



R. G. Hatfield is credited with sonic of the best exiieriinents on siieariiig strength, published 

 in the American House Carpenter. 



Prof. G. Lanza's experiments are largely reproduced, also Trautwinc's on shearing, and some 

 of the author's own work on California Sjiriice, Oregon I'iiie. and others, esjiecially in torsion, 

 with a specially constructed machine, an interesting plate of strain diagrams accompanying the 

 discussion. 



In connection with the discussion on the influence of iirolonged stress by the author, there is 

 quoted as one of the older investigators Herman Haux)t, whose results on yellow lu'ne were ]nih- 

 lislied in 1871 (Bridge Construction). 



Experiments at the Stevens Institute of Technology are related, with thi^ important conchisiou 

 that a load of 60 per cent of the ultimate strength will break a stick it left loaded (one small test 

 piece having been left, loaded fifteen months with this result). 



Ill addition the following list of references to American work in timlx^r ])liysic,s is here inserted, 

 with a regret that it has iiotbeen i)ossiblt! to include all the stray nol(^s which maybe in existence 

 but were not accessible. Those able to add further notes are invited to aid in making tiiis refer- 

 ence list complete. 



Abbott, Arthur V. TListinj; macliiucs, their history, coustruction, aud use. Witli illustrations of machines, includ- 

 ing that at Watcrtowu Arsenal. Van Xostrand's Magazine, vol. 30, 1883, ]>p. 204, 325, 382, 477. 

 Day, Frank M., University of Pennsylvania. The microscopic examination of timber with regard to its 8treu),th. 



Read before American Philosophical Society, 1883. 

 Estrada, E. D. Kxperiinents on the strength aud oth(!r properties of Cuban woods. Investigations carried uu in 



the laboratory of the Stevens Institute. Van Nostrand's Magazine, vol. 2i), 1883, \>\<. 417, 141. 



Flint, . Report of tests of Xicanigua woods. .lourual of Fraulcliu Institute, Octidirr, 1887, pp. 289-31."). 



Goodale. Prof. George L., Harvard rniversity. Physiohigical Hotany, 188."i. chapters 1, 2, 3, .">, 8, 11. and 12. 

 Ihlseng, Magnus C, Ph. D". On the iiindiiliis of elasticity in sonic AmcricuTi woods, deterniiiiid by viliration. \ai) 



Nostrand's Magazine, IS), 1S78. 

 — . On aniodc of measuring the velocity of sounds iu woods. Head licfore the National Academy of Science, 



1877; published in ,\nieriiMU .lournal of Science and Arts, vol. 17, lS7i(. 

 Johnson, Thomas II. I)n the strength of columns. Paper read at annual rorivi'ution of American Society of Civil 



Engineers, 188.5. Transactions of the Society, vol. 15. 

 Kidder, F. E. Experiments at Maine .State Collegi'ou Iransversi; strength of southern ;nHl \\ liile jiine. VauNostrand'a 



Miigazine, vol. 22, 1879. 



. Experiments with yellow and white pine. Van Nostrand's Magazine, vol. 23, 1880. 



. Experiments cm the strength aud stitfness of small spruce beams. Van Nostrand's Magazine, vol. 24, 1880. 



. Influence of time im bending strength and elasticity. Journal of Franklin Fnslitute, 1882. Proceedings 



Institute of Civil Engineering, vol.71. 

 L.anza, Gaetauo, professor Massachusetts Institute of Tiu'hnology. .Viblri'ss bclore American Society of Mechuuiual 



Engineers, describing the .")l),00()-i)ound testing miicbiuc at Watcrtown Arsenal and tests of strength of large 



spruce beams. Journal i>l' l.'ranUliM lusti(u^(^, ISSIJ. 



