428 
Proceedings of the Royal Society 
include a few papers of a kind which cannot be well brought under 
any of the groups adopted in the preceding arrangement. But 
some of these merit attention. 
Dr Donald Monro describes in 1783 the mode at that time 
followed in India for obtaining attar of roses without having re- 
course to distillation. This method consists simply in exposing for 
six or seven days to the sun picked rose-petals, merel 3 *covered with 
water, in an earthenware jar, and removing with a pellet of cotton 
on a stick, the volatile oil which gradually forms on the surface. 
Roebuck communicates in 1798 experiments on the effects of com- 
pressed air, made by him in the air-vault of the blowing apparatus 
of the Devon Iron-works. Only one man was found so venturous 
as to go with him into the air-vault while the steam-engine was 
working. The vault was 72 feet long, 14 feet wide, and 13 feet 
high ; and the compressing force was 2 75 pounds per square inch, 
by which a mercurial column was raised between five and six inches, 
adding, therefore, nearly a fifth to the mean pressure of the atmo- 
sphere. He observed a sense of pressure on the ears, great increase 
of sound, no perceptible augmentation of heat, but a damp sensa- 
tion which speedily passed off. No inconvenience was felt during 
the hour that the experiment lasted. Sir James Hall, in a disserta- 
tion on the Origin of G-othic Architecture, deduces ingeniously the 
Gothic arch from the form assumed by tree poles bent at the top 
to meet or cross one another, and the florid ornaments of the arch 
from spontaneous fractures and outward bending of the tree bark on 
the curves of the arch as the bark dries. Sir Gilbert Blane endea- 
vours to trace the Arabic figures for numerals to India. Lord 
Ancrum proposes improvements in the arms and accoutrements of 
cavalry, principally for lessening the weight on the horse, and 
facilitating the movements of the horseman. Clerk of Eldin shows 
his well-known nautical propensities, by proposing a scheme for 
raising sunken ships. 
According to custom, I annex a statement of the changes which 
have taken place during the last twelve months in the membership 
of the Society. 
In November 1867 the Society consisted of 56 Honorary Fellows 
