• Cave, I.D.
  Department of Scientific and Industrial Research, Lower Hutt, New Zealand
  

The theory of the method proposed by Meylan for the measurement of the mean mocrofibril angle in wood is presented. A new measure of the width of the (002) diffraction arc T, defined on practical grounds, is shown to have theoretical advantages over other methods in use. Using models of the cellulose microstructure of wood it has been shown that linear relations between T and the mean microfibril angle exist. The theory supports the linear experimental relation between T and iodine staining angle, if the models used assume a normal angular distribution of microfibrils with standard deviation equal to one-third of the mean microfibril angle. In this case, cell cross-sectional shape does not greatly influence the T mean microfibril angle relationship..