76 NOTICES OF THR MEETINGS (May 23, 
chyma, which was relatively negative. As the earth is relatively 
negative to the serene atmosphere above, it would appear that 
the vegetative process acts in a direction contrary to that of 
the causes which give the earth and air around it their relative 
electric states. (Vide Annales de Chimie, 1851, tome xxxi. p. 40.) 
In the Library were exhibited — 
Maps and Views of Central America and Drawings of the Inhabitants, 
Antiquities, Animals, and Plants [by Capt. Shippard]. 
The Trogon Resplendens and other birds from Central America 
[by Messrs. Leadbeaters]. 
A small gold figure from Bogota-— Models of a boat built for 
Capt. Parry’s Polar Expedition, and a cutter by Mr. T. 
Roberts; an Indian Gun; Mocassins, &c. [by the United 
Service Institution]. 
WEEKLY EVENING MEETING, 
Friday, May 23. 
Tue Rey. Jonn Bartow, M.A., F.R.S., Secretary R. I. 
in the Chair. 
Witusam Hosxine, Esa. 
PROFESSOR OF ARCHITECTURE AND OF ENGINEERING CONSTRUCTIONS AT 
KING’S COLLEGE, LONDON. 
On Ventilation by the Parlour Fire. 
Tue term Ventilation does not strictly imply what we intend by its 
use in reference to Buildings used as dwelling-houses, or otherwise 
for the occupation of breathing creatures. To ventilate is defined 
“‘to fan with wind ;”’ but one of the main objects for which houses 
and other enclosed buildings are made, is shelter from the wind, 
Inasmuch, however, as the wind is but air in motion, and we can only 
live in air, air may not be shut out of our houses, though, for 
cormfort’s sake, we refuse to admit it in the active state of wind. But 
in doing this — in shutting out the wind,-— we are apt to put ourselves 
upon a short allowance of air, and to eke out the short allowance by 
using the same air over and over again. 
There is a broad line of distinction, indeed, to be drawn between 
in-door and out-door ventilation ; for although the principles upon 
which nature proceeds are the same, the operation is influenced by 
the circumstances under which the process may he carried on. 
Whether it be on the hill-side, open to the winds of heaven, or ina 
close room from which all draught of air is excluded, the expired 
