ยง 1. Introduction. Extractives play an important part in the study and application of wood. In several species they confer durability to heart wood. For example the durability of the heart wood of Callitris sp. is ascribed to the presence of 1-citronellic acid and of western red cedar to thujaplicins (isopropyl tropolones, vide N a r a y a n a m u r t i 1)). Extractives m a y also influence other properties, like hygroscopicity and shrinkage and swelling (vide T r e n d e l e n b u r g 2)) gluability ( N a r a y a n a m u r t i , D.3)), pulping and the plasticity of the wood cell wall substance ( K o l l m a n n 4), K o l l m a n n and N a r a y a n a m u r t a), and N a r a y a n a m u r t i , D., G u p t a and N a r a y a n a m u r t i , V. 6)). L u x f o r d T ) noticed that extractives can influence the strength properties of wood, but the effect varied with the nature of the stress. He found the maximum crushing strength was most favourably affected by the amount of extractives present. According to A r m s t r o n g s). the abrasion resistance of tropical woods is higher, the higher the resin content. Such extractives also impart a natural polish when the timbers are worked with tools. Apart from durability studies, as no data are available in the case of Indian timbers, in connection with work on the influence of various factors on tile production and properties of modified wood, a study of the influence of extractives on the modulus of rigidity in torsion was made on some species of Indian timbers. ยง 2. Material used/or the investigation. Heartwood veneers of the following species were employed in the study: Adina cordi/olia (haldu), Dalbergia lati/olia (rosewood), Dalbergia sissoo (sissoo),