XXX Appendia. 
certain proportion of forest area. Marsh, in his well-known work on 
“ Man and Nature," published in London in 1864, says :—‘ One important 
conclusion at least upon the meteorological influence of forests is cer- 
tain and undisputed, the proposition, viz., that within their own limits 
and near their own borders they maintain a more uniform degree of 
humidity in the atmosphere than is observed in cleared grounds.” And, 
again, writing of the indiscriminate clearing in America ;—‘ With the dis- 
appearance of the forest all is changed. At one season the earth parts 
with its warmth by radiation to an open sky, and receives at another heat 
from the unobstructed rays of the sun; hence the climate becomes exces- 
sive, and the soil is alternately parched by the fervour of summer and seared 
by the rigours of winter. Bleak winds sweep unresisted over its surface, 
drift away the snow that sheltered it from the frost, and dry up its scanty 
moisture." Innumerable quotations could be given and irrefutable 
evidence adduced from the works of Hooper, Schleiden, Becquerel, Hum- 
boldt, and Boussingault, all tending in the same direction. The Rev. W. 
B. Clarke, F.R.S., ete., recently read a paper before the Royal Society of 
New South Wales, on the subject of the “Effects of. Forest Vegetation on 
Climate," with the general tone and direction of which I cordially eoneur, 
though unable to agree with him in all his deductions and conclusions. He 
quotes largely from Schleiden and Marsh, and gives an extract from an 
essay by the late Sir Henry Holland, in the « Edinburgh Review," viz.:— 
“It is the forest which actively ministers to the climatic condition of the 
earth, which, extirpated by the axe or restored by planting, changes both 
the face of nature and the distribution and destinies of human life." The 
case of some parts of Africa and Asia Minor, the Mauritius, St. Helena, 
Ascension, Madeira, etc., have all been given by various writers, and quite 
lately Dr. Croumbie Brown, formerly Government Botanist at the Cape, 
has done excellent service by publishing a series of works on the subject 
entitled “The Hydrology of South Africa," “ Reboissement in France,” 
** Forests and Moisture, or Effects of Forests on Humidity of Climate,” the 
last of which I have not seen. Professor Laurent of the Forest School at 
Nancy, has also written on the subject, and “ instances Fontenoy and Pro- 
vence as places where the felling of forests has affected the climate.” So 
much for the influence of forests on climate generally. We next come to 
that of their effect on the water supply and its regulation. Most of the 
authorities already quoted have written also on this point, but I prefer 
quoting from other sources of more recent dates. The paper by Monsieur 
Clané, from which I quoted in my Dunedin lecture, is a clear and exhaustive 
treatise on the subject. He refers to actual observation made by MM. 
Becquerel and Boussingault, and to those of M. Mathieu, of the Forest 
