ME. LUTHER ROBINSON’S 
PLAN FOB VENTILATING 
THE WINGS OF THE 
UNITED STATES CAPITOL. 
June, 1870. No. 46 Congress Street, 
Boston, June 10th, 1870. 
To the Congressional Committee on Ventilation, Washington: — 
Gentlemen, — The failure of most attempts to secure the 
satisfactory ventilation of buildings clearly proves that they have 
been made without regard to the true principles, on the right 
application of which, alone, success depends. 
All simply “ejecting” plans, with or without the aid of heat, 
are wrong in theory; and are, therefore, as proved by universal 
experience, inefficient and unsatisfactory in practice; and all 
forcing plans are costly, for machinery, power, and care, even if 
excellent results can be secured, — and, as to results, I have seen 
many cases of failure, and none of marked success. 
The philosophical reasons for their failure it is easy, but not 
necessary, now to state. 
It is not my present purpose to write a general essay on 
Ventilation, nor to correct, describe, or discuss, unless briefly and 
incidentally, the various theories on this subject, nor even to recall 
to your minds the several interesting collateral questions often and 
properly discussed in this connection, presuming all these to be as 
familiar to the Committee as to myself. 
My purpose is, rather, to propose a definite 'practical plan for 
securing, beyond the possibility of failure, a highly satisfactory 
condition of the atmosphere in the Legislative Halls in the Capitol 
in Washington. 4 
After full and careful study of the philosophy, operation, and 
results of all systems in use in this country, and with an experience 
in ventilating many hundreds of buildings, small and large, with 
the most complete success, without an approach to a failure, — in 
the last six years, at least,—I can speak on this subject with 
the confidence of knowledge not merely theoretical. 
I have fully considered the construction and circumstances of 
your Legislative Halls, and know precisely what is needful to make 
their atmosphere constantly fresh and comfortable, and shall offer 
to ventilate one or both of them, in accordance with the general 
plan herein indicated, executing all mechanical work in style and 
manner entirely satisfactory to the Committee, after examination; 
also, securing and warranting results entirely satisfactory after a 
reasonable trial, on terms to be named in separate, more detailed 
specifications and proposal, soon to be made. 
The proper ventilation of the Capitol, as of other buildings, 
requires the furnishing of an abundant supply of fresh air, its 
proper distribution, and the effectual removal of air from the 
building. 
By the system of ventilation which I have orally explained to 
you, all of these objects are satisfactorily accomplished. 
Beyond all doubt, fresh air is furnished, and impure air 
efficiently removed, and, with proper skill in the application of 
the system, without annoyance from currents. 
To the roofs of buildings we apply structures of iron or other 
material,— ventilators, of peculiar construction, having mouths open 
in every direction, subdivided by several partitions, with tubes, 
straight or angular, long or short, as needful, subdivided to corres- 
pond with the divisions of the ventilators, extending through the 
upper portion of the building, and reaching proper points in the 
ceiling of the room to be ventilated. We thus establish communi- 
cation through numerous passages, between the room and the 
external air. 
Through these ventilators and connecting tubes, alternating 5 
currents of air pass. Through some of them fresh air passes in, 
and is properly distributed, while through others impure air passes 
out, securing thus the real, efficient, quiet change of air, which con- 
stitutes good ventilation. 
This is not theory, but fact, easily ascertained by intelligent 
examination of any one of the thousands of these ventilators 
already in use; and the results of the change are manifest to the 
most casual observer. 
Over the Capitol, and within ten feet of its roof, an abundance 
of air passes, every day in the year, to ventilate, even excessively, 
more than a score of such buildings. It moves with a momentum 
varying with its velocity, but ever sufficient for our purpose. 
We use this undoubted “power of the air” as one of two 
forces to accomplish our end. Whatever its velocity or direction, 
it presses against some face and into some mouth or mouths of these 
ventilators, and is conducted through some of the tubes to the room, 
as surely as water and illuminating gas, under pressure, are driven 
through their pipes to distant points for convenient use. 
The necessary consequence of this influx of air is condensation, 
if the room is tight, or exit if not tight. But with the construction 
described there can be no condensation, as some faces under the lee 
must be less pressed than those against which the wind blows, 
allowing easy exit to the air driven out in consequence of the 
entrance of air on the opposite side. 
This operation is visible to all who, on a frosty day, pass any 
of the three hundred drying and dressing rooms on which these 
ventilators are used. 
From three rooms of this class, under control of members of 
the present Congress, moisture enough has already been removed, 
to form, when condensed, not less than forty thousand barrels of 
water. 
The ordinary heat of a room, from whatever source derived, 
acts as another motive force, establishing and keeping up this same 
alternation of currents, even without the aid of wind, 6 
Heat drives air through some of these passages, and not 
through all of them, while external air, even by its weight alone, 
falls in to supply its place. 
This is demonstrable fact, which no argument can make more 
plain, nor any theorist disprove. 
Thus, considering the impure air of a room simply as matter, 
subject solely to the laws of force, moving only as moved, we have 
at our command, and through these structures use, as forces, wind 
and heat, acting efficiently, separately or concurrently, effecting the 
desired change of air. 
We thus provide for the efficient and quiet ventilation of any 
building, at all times, unless in the extremely rare but theoretically 
possible case of the failure of both forces. 
But if, by respiration and radiation the temperature of the air 
is not increased, and if, at the same time, there is no appreciable 
movement of the external air, it is perfectly safe, and may add to 
comfort, to open all dooi*s and windows. 
Providing, as we do, for all cases in which it is desirable 
to close them because of the discomfort due to cold air or to 
currents; securing, as we do, at all such times, results closely 
bordering on perfection; we need not be too solicitous in regard 
to a possible conjuncture of conditions which may not exist during 
a single hour in a year, and for which provision can be made only, 
even ie, by “ mechanical power,” already at your command. 
Our ventilators standing on the roof, so low as not to be 
conspicuous from the ground, should be sufficiently large and 
numerous to correspond to the wants of the largest audience; 
only a portion of them being in use when the audience is small. 
The tubes or boxes in the attic would need to be very large 
and complicated, extending over the entire galleries on all sides of 
the halls. 
The ceiling over these galleries is very open, affording all or 
nearly all of the needed space. 
In the ceiling of the Senate Chamber, no change would be 7 
needed, and, in that of the House, only an enlargement of the open- 
ings at about 200 points, between the brackets, next to the walls on 
all sides of the hall, — a change not noticed unless on close 
inspection. 
All of these pores in the ceiling would be used for the actual 
passage of the incoming and outgoing air. 
They are admirably arranged for its proper' distribution, in 
streams mild as the gentlest shower, the rising vapor, or the falling 
snow. 
The halls might almost be said to breathe, taking in the good 
and expelling the bad air. If all breathe in unison, the halls as fast 
as the audience, as they may, nothing better can be required. Let 
the carbonic acid, observant of fundamental law, float into the 
outer air, as it will, all authorities and all theories “ to the contrary 
notwithstanding,” and we need have no fear that vegetation will 
fail to perform its work, and make the needful restoration. 
From this “carbonic acid question,” on which no darkness 
needs to rest, it would afford me pleasure, if time allowed, to brush 
the mists and myths with which false teaching has surrounded it. 
Orally, I often discuss it in full, and shall be pleased thus to give 
to the Committee, if they desire, the facts and the law of the case. 
Not merely these large halls, but their surroundings also can 
be vastly improved. 
Over each stairway, besides the glass, is a very extensive 
porous ceiling. 
All of this open space I would convert into immense respirators, 
our large, complex, and very angular boxes covering the whole, 
and connecting it with giant ventilators standing on the roof over 
the passages at the head of the stairs. 
Through our ventilators and boxes thus arranged, injection 
and ejection will be effectually accomplished, securing throughout 
the stairways and connecting passages a state of freshness hitherto 
unknown, and not attainable, unless at enormous cost, by any other 
known plan. 8 
All the rooms opening into these passages, especially those 
above the first story, will be improved in condition; and most or all 
of those occupied by few persons may be sufficiently ventilated by 
the frequent opening of doors, allowing direct communication with 
a reservoir of fresh and constantly changing air. 
There can be no doubt as to the operation and results above 
indicated, as I have at least a score of successful similar cases. 
The effect, I have no doubt, will be appreciable even below 
the level of the floor of the Legislative Halls, but in all the space 
above that level it cannot fail to be most marked. 
These ventilators should be so large that if 3,000 persons 
should occupy the stairways %md passages in each wing, with all 
doors and windows closed, there would be no suffering for want 
of pure air. 
This arrangement alone would be of vast benefit to the occu- 
pants of the Legislative Halls, especially when the audience is 
large, as all doors from the halls would be likely to be then open. 
Such, Gentlemen, is the general plan which I shall offer to 
apply to the wings of the Capitol. 
Its universal success, wherever properly applied, is an index of 
what we may expect in the future. 
In the House, a few weeks since, reference was made to the 
discomfort due to heat from the burning of gas above the ceiling. 
A plan for securing almost complete protection from that 
annoyance can be easily applied. 
Very respectfully, 
LUTHER ROBINSON, 
Agent of U. S. Ventilation Co., 
of Boston.