J. F. Martley 225 



In order to continue his work on the warping and twisting phenomena 

 shown by these woods and to investigate their structure Professor Percy 

 Groom secured through the kindness of Mr R. 8. Pearson, Imperial 

 Forest Economist, India, portions of the trunks, in the form of cylindrical 

 drums several feet or more in length, of the undermentioned Indian trees. 

 These Professor Groom entrusted to me to make this preliminary in- 

 vestigation into the true nature of this type of cross-grain: 



Flacourtia Cataphracta Roxb. Bixaceae. 



Pent-acme suavis D.G Dipterocarpaceae. 

 Shorea robusta Gaertn. „ 



Pterospermum acerifolium Willd. Sterculiaceae. 



Garuga pinnata Roxb. Burseraceae. 



Chloroxylon Swietenia D.G Meliaceae. 

 Cedrela Toona Roxb. ,, 



Pterocarpus Marsupium Benth. Leguminosae. 

 Ougenia dalbergioides Benth. „ 



Dalbergia Sissoo Roxb. ,, 



„ latifolia Roxb. „ 



„ Oliveri Gamble. ,, 



Xylia dolabriformis Benth. ,, 



Hardwickia binata Roxb. „ 



Anogeissus latifolia Wall. Combretaceae. 



Schrebera swietenoides Roxb. Oleaceae. 



Gmelina arborea Linn. Verbenaceae. 



M allot us philippine nsis Muell. Euphorbiaceae. 



Holoptelea integrifolia Planch. Ulmaceae. 



Before I received the material each drum had been sawn up into a 

 number of half-inch boards of which only two at the most were truly 

 radial. In addition there was a transverse disc, a little over an inch 

 thick, for each species, but there was nothing to indicate whether the 

 disc and drum had been contiguous, or separated, in the log from which 

 they had been sawn. 



Methods of Investigation. 



The methods of investigation into the course of the grain can be 

 classified under two headings, namely: (1) Preliminary Investigations, 

 and (2) Detailed Investigations. The former deal with the methods of 

 attacking the problem, while the latter are concerned with the actual 

 investigation. 



