ON INVESTIGATION OF THE JURASSIC FLORA OF YORKSHIRE. 245 
during the past three years until the existing collections have been 
fully investigated. 
The Committee does not seek re-appointment. 
The Vegetation of Ditcham Park, Hampshire.—Interim Report 
of the Committee, consisting of Mr. A. G. TANSLEY (Chair- 
man), Mr. R. 8. ApAmson (Secretary), Dr. C. E. Moss, and 
Professor R. H. Yapp, appointed for the Investigation thereof. 
Since the date of the last report a large number of experiments have 
been carried out with evaporimeters. Especially, a large series of 
simultaneous readings have been taken, covering a considerable period, 
from instruments placed in various positions in beech-woods, coppices, 
and in open grassland. Several of the results suggest further lines of 
experimentation and research, but a much larger number of readings 
must be obtained before any generalisation can be enunciated. The 
evaporimeter readings have been run concurrently with a series of 
readings of wet and dry bulb thermometers, and also of maximum and 
minimum thermometers which have been placed in association with the 
evaporimeters. 
The work on soils has commenced, but so far has been mainly . 
preliminary. Experiments have been made on soil temperatures, 
especially in relation to exposure, drainage, woodland canopy, &c. 
The general preliminary mapping of the various associations com- 
posing the area has been completed, and an analysis of them has been 
made from the topographical and floristic standpoints as a basis for 
experimental work in the coming season. In this connection special 
attention has been paid to the successive changes occurring after 
coppicing till the re-forming of the full canopy, and also to the question 
of the recolonisation by trees of cleared areas and grasslands. Data 
_ been collected which serve as a starting-point for a more detailed 
study. 
The areas enclosed against rabbits, &c., have also been under 
observation, and the changes occurring have been examined and 
recorded. 
The Committee asks to be reappointed, without a grant. 
Experimental Studies in the Physiology of Heredity.—Report of 
Committee, consisting of Professor F,. F. BuackMAn (Chair- 
man), Mr. R. P. Grecory (Secretary), Professor W. 
Bateson, and Professor F. KEEBLE. 
Tue grant of 301. has been expended in part payment of the cost of 
experiments conducted by Miss E. R. Saunders, Mr. R. P. Gregory, 
and Miss A. Gairdner. Miss Saunders’ experiments with stocks have 
had for their main objects :— 
(1) The investigation of the condition known as half-hoariness and 
