HISTORY OF THE SOCIETY. 575 
a letter to Henry Witham, Esq., illustrated by sections of 
the Borino;s for coal. — Dr John Aitken then exhibited a 
number of very fine Anatomical Preparations, and gave 
from them a demonstration of the circulation of the blood 
in the foitus, in man, and in several of the lower animals, 
particularly the cow, the red deer, the dog, and the seal. — 
The members of the Society afterwards proceeded to Dr 
Roper's Laboratory, to witness a beautiful experiment, 
shewing the intense light and heat produced by passing up- 
on an ignited ball of lime, placed in the focus of a light- 
house reflector, a continued stream of hydrogen gas. 
1830. 
David Falconar, Esq. V. P. in ihe chair.— -The Secre- Peb. 6. 
tary read a memoir by Mark Watt, Esq. on the Power 
which certain Spiders possess of fixing their threads hori- 
zontally between two perpendicular bodies placed at a dis- 
tance from each other. Likewise, a notice regarding a sort 
of Fascination practised on small birds by the Whitret or 
Weazel ; in a letter from the Rev. Alexander Duncan of 
Mid-Calder. — The Rev. Dr Scot then read an essay on the 
Dishong of Moses, or Gazelle of the Plain, the ' Pygarg ' 
of the English Bible. 
David Falconar, Esq. V. P. in the chair. — There was Feb. 20. 
read an account of several new species of Grouse recently 
discovered by Mr David Douglas among the Rocky Moun- 
tains, communicated by James Wilson, Esq. ; the speci- 
mens at the same time being placed on the table. — The 
Rev. Dr Scot read an essay on the Mustard Plant men- 
tioned in the Gospels, shewing that it was probably the 
Sinapis nigra, which grows five or six feet high in warm 
countries, rather than the Phytolacca decandra, which pro- 
bably did not exist in J udea. 
