Obituary—C. T. Clough. 525 
Dr. C. H. Desch read a paper, illustrated by lantern slides and 
specimens, on ‘‘ The Origin of Agates’”’. The most puzzling question 
in regard to agates was the parallel banding of the chalcedony of 
which they were chiefly composed. This had usually been regarded 
as representing successive flows of liquid containing gelatinous silica, 
which was deposited in thin layers on the walls of the cavity in which 
the agate was formed. Certain features common in agates were 
regarded as ‘‘tubes of entry” or ‘‘tubes of escape’’. In 1867 
Ruskin had brought forward evidence to show that the banding was 
due rather to segregation in the solid state, but no theory as to the 
mechanism of the process could then be given. The work of Liesegang 
on rhythmical precipitation in gelatinous masses had led to the 
production of objects in which all the characteristic features of 
agates, including the ‘‘ tubes of escape’’, were exactly imitated by 
processes of simple diffusion. It was not even necessary to assume 
precipitation. Slides were shown to prove that rhythmical crystal- 
lization, giving rise to a banded structure, could be observed even in 
pure substances. It was sufficient to assume a process of rhythmical 
erystallization in a mass of gelatinous silica to account for the banding 
and other characteristic features of agates. 
OBITUARY. 
Gane CLOUGH; 
M.A., LL.D., F.G.S., F.R.S.E., of Geological Survey of Great Britain. 
BoRN DECEMBER 23, 1852. DIED AUGUST 27, 1916. 
N accident on the railway near Bo'ness has cut short the life of 
one of the most widely known and deeply respected of British 
geologists. Dr. Clough in the course of field-work in that district 
had occasion to cross the railway. Some mineral wagons were being 
_ shunted at the time and he tried to passin front of them, but was run 
over. Immediate attention was given to him, first by the railway 
staff, and thereafter by the surgeons of Edinburgh Infirmary, to 
which he was sent by special train, but his injuries were very 
serious, involying double amputation, and after lingering for three 
days he died on Sunday, August 27, 1916. He was buried in 
Lasswade Churchyard on Wednesday, August 30. 
Dr. Clough was 63 years of age. He joined the Geological 
Survey in March, 1875, at the age of 22, and after forty-one years 
was on the eve of retiring, but consented to remain on the staff 
to assist in meeting the pressure of work entailed by the absence on 
active service of most of the junior members of the Survey. 
He was educated at Rugby, and at St. John’s College, Cambridge, 
which he entered in October, 1871. He was awarded an exhibition 
in Natural Science from 1872 to 1874. In 1873 he obtained a first 
_ class in the May examination. In 1874 he received a first class in 
the Natural Science Tripos, being bracketed second with Herbert 
Carpenter, J. N. Langley, R. D. Roberts, and C. E. Shelly. He 
was elected a scholar in 1874-5, and took his B.A. in 1875 and his 
M.A. in 1878. 
