150 Ventilation for human beings. 
October 14th 1887. I have thought much how to ventilate for human beings. 
From the bees comes the suggestion of a current of bad air forced out, to be 
replaced by a current of pure air. Done by the fanning ventilators, just as the 
air of a sick chamber may be renewed without opening windows, by the so called 
pumping process with a door opening into any place where there is good air. 
Ventilation artificial for men, is the establishment of this double current. 
How to do this where a current of warm pure air can be brought in and another 
of impure air carried out, is well known. The difficulty if not [illegible] of 
heating many rooms at different elevations and different distances from the 
hot air chamber, amounts often to an impossibility. If all is working to 
satisfaction on a mere change in the force or direction or both of the winds may 
cause some rooms to be too warm while others are too cold. It has become quite 
common therefore to heat by radiators with steam or hot water. In one way this is 
a success, as the proper amount of radiating surface can be secured and 
the requisite heat obtained and controlled. But this gives no ventilation. It 
is on the old box or [illegible] stove system. Now the radiators heating the air 
if there are proper [illegible] for it to pass off, it will be easy to get rid of the 
impure air, and replace it by fresh air which will force itself in at every 
crack, window etc. whenever it has a chance. It is easy to apply this system 
to all buildings where there is ready access to any steeple, tower etc. If a church 
or any building must be heated by hot air. Let there be from the audience 
room by register and air duct the means of supplying air to the heating 
chamber. Say the air in the audience room is 40 degrees, out of doors, zero. The 
40 degree air is sent down and up and the room heated much sooner than by 
using the zero air. This answers if the air is as it readily may be, made pure to 
begin with. Just as soon as the air of the audience room is being [illegible] by 
human beings, it is no longer allowed to revolve, but fresh air from outside is 
introduced to the heating chamber. If there is no ready escape for the [illegible] air 
to pass out, the heater works to great disadvantage. To get pure warm air into the 
room you must force out air already there. To this is to let in much less hot 
pure air than you desire, the current is too slow to carry off all the heat that 
ought to be available from the heater. To counteract this the heater is overwork,
fuel wasted and the pure outdoor air [illegible] by red hot or overheated
metallic surfaces. In addition the very hot air that comes from the heater chamber 