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LECTURES ON VENTILATION:

  BEING A COURSE DELIVERED IN THE FRANKLIN INSTITUTE, OF PHILADELPHIA,
  DURING THE WINTER OF 1866-67.


BY LEWIS W. LEEDS,

    Special Agent of the Quartermaster-General, for the Ventilation
    of Government Hospitals during the War; and Consulting Engineer
    of Ventilation and Heating for the U. S. Treasury Department.


=Man's own breath is his greatest enemy.=


  NEW YORK:
  JOHN WILEY & SON, PUBLISHERS,
  2 Clinton Hall, Astor Place.
  1869.



  Entered according to Act of Congress, in the year 1868, by
  LEWIS W. LEEDS,
  In the Clerk's Office of the District Court of the United
  States for the Southern District of New York.


  New York Printing Company,
  81, 83, _and_ 85 _Centre Street_,
  New York.




PREFACE.


These Lectures were not originally written with any view to their
publication; but as they were afterwards requested for publication in the
Journal of the Franklin Institute, and there attracted very favorable
notice, I believed the rapidly increasing interest in the subject of
ventilation would enable the publishers to sell a sufficient number
to pay the expense of their publication; and, if so, that this very
spirit of inquiry which would lead to the perusal of even so small a
work, might be one step forward towards that much-needed more general
education on this important subject.

It was not my desire to give an elaborate treatise on the subject of
ventilation. I believed a few general principles, illustrated in a
familiar way, would be much more likely to be read; and, I hoped, would
act as seed-grain in commencing the growth of an inquiry which, when once
started in the right direction, would soon discover the condition of the
air we breathe to be of so much importance that the investigation would
be eagerly pursued.

                                                               L. W. L.




CONTENTS.


LECTURE I.

    Philadelphia a healthy city--Owing to the superior ventilation
    of its houses--But the theory of ventilation still imperfectly
    understood--About forty per cent. of all deaths due to foul
    air--The death rate for 1865--Expense of unnecessary sickness--In
    London--In Massachusetts--In New York--In Philadelphia--Consumption
    the result of breathing impure air--Entirely preventable--Infantile
    mortality--Report on warming and ventilating the Capitol--Copies
    of various tables therefrom--Carbonic acid taken as the
    test, but not infallible--The uniform purity of the external
    atmosphere--Illustrated by the city of Manchester--Overflowed
    lands unhealthy--Air of Paris, London and other cities--Carbonic
    acid in houses--Here we find the curse of foul air--Our own
    breath is our greatest enemy--Scavengers more healthy than
    factory operatives--Wonderful cures of consumption by placing
    the patients in cow stables--City buildings prevent ventilation,
    consequently are unhealthy--The air from the filthiest street
    more wholesome than close bed-room air--Unfortunate prejudice
    against night air--Dr. Franklin's opinion of night air--Compared
    with the instructions of the Board of Health, 1866--Sleeping with
    open windows--Fire not objectionable--A small room ventilated is
    better than a large room not ventilated--Illustration--Fresh
    air at night prevents cholera--Illustrated by New York
    workhouse--Dr. Hamilton's report--Night air just as healthy
    as day air--Candle extinguished by the breath--The breath falls
    instead of rises--Children near the floor killed first--Physicians'
    certificates do not state "killed by foul air"--Open fire-places
    are excellent ventilators--All fire-boards should be used for
    kindling wood--Illustration showing when ceiling ventilation
    is necessary.

                                                                 PAGE 3


LECTURE II.

    The effect produced by heat upon the movements of air--Air
    a real substance--Exerts a pressure of fifteen tons on an
    ordinary sized man--It cannot be moved without the expenditure
    of power--The sun's rays the great moving power--They pass
    through the forty-five miles of atmosphere without heating it,
    and heat the solid substances of the earth's surface--Experiments
    showing the effect of radiant heat and reflected heat--The air
    of the room not pure and dry--The ordinary moisture absorbs
    from fifty to seventy times as much as the air--Many gases
    absorb much more--The moisture in the air the great regulator of
    heat--Air is heated by coming in immediate contact with hotter
    substances--Impossibility of any air remaining at rest--The
    practical application of these principles--The open fire acts like
    the sun, heating by radiation only--Probable electric or ozonic
    change in furnace-heated air--The stove heats both by radiation
    and circulation--The stove nor the open fire not suitable for
    large crowded rooms--Circulating warmed air best--Erroneous views
    in regard to ventilation--Experiments with liquids of different
    densities--When warming and ventilating by circulating air, the
    escape for the used air should be from the bottom of the room--But
    when ventilating with cooler air the escape should be from the
    top of the room--Windows should lower from the top and flues open
    at the bottom of the room--The fashionable system of heating by
    direct radiation, without any fresh air, very objectionable.

                                                                PAGE 18


LECTURE III.

    One breath of impure air shortens our life--Difficulty of getting
    pure air to breathe in houses and cars--Foul air in steam
    cars--Want of the proper knowledge regarding ventilation among
    all classes--Want of ventilation in this lecture room--Want
    of ventilation in the Cooper Institute, and in many other new
    and splendid buildings--Street cars very foul--My own chamber
    fully ventilated--I have no new patent idea, sufficient for all
    time without further thought--Constantly varying conditions
    require separate intelligent thought and action--The air
    moves horizontally in summer--Flues are then of no account--We
    must depend on open doors and windows--How to ventilate a sick
    room in the morning--The same in the evening--Windows should
    always lower from the top--To make air move in the summer is
    the great desideratum--When in motion the cold air falls and
    warm air rises; when at rest, it is arranged in horizontal
    layers, according to temperature--A flue is simply a passage
    for air of different temperatures--Experiments with flues
    of different temperatures--Expansion of air by heat--Weight
    required to keep it from expanding--Heating air weakens it
    instead of giving it power--Experiments showing draughts by
    lighted candles--Ventilation of churches--Illustrations not
    exaggerated--Examination of church in neighborhood--Fresh air
    taken from foul cellar--No fresh air supplied to churches used as
    hospitals in Washington--Depending on a sham ventilator painted
    on the solid wall--Foul air in Philadelphia schools--New York
    public schools--Many of the ventilators perfect shams--Covered up
    air-tight by the capping stones--Importance of the evaporation
    of water--A strong fire in basement will draw gas out of
    second story stove--A strong fire up stairs will draw foul
    gases from untrapped sewers--A very healthy location may
    thus be made very unhealthy--Drs. Palmer, Ford and Earle's
    report of epidemic at Maple Wood Institute--An arrangement for
    ventilation that ought to be in every house--Flues generally
    too small, especially in Philadelphia--Very large ones put in
    government hospitals, which proved thoroughly efficient--The
    leading points in regard to heating--The fresh air must be
    warmed before entering in winter--A hot water furnace requires
    additional moisture--Heating by steam--Steam-pipes ought to be
    laid through the street the same as gas and water--Two-thirds
    of heating surface should be for heating the fresh air and one
    third for direct radiation--Forty pounds of water required to
    be evaporated every minute for U. S. Senate Chamber--All stoves
    should have fresh-air boxes--Dampers in fresh air-boxes not
    good--Experience has fully demonstrated that careful attention
    to these things will be amply rewarded by increased health,
    strength, happiness and longevity.

                                                                PAGE 31


    Article relating to the Grand Prize awarded to Hospital Ventilation
    and other Sanitary arrangements, Paris Exhibition.

                                                                PAGE 51




LECTURES ON VENTILATION.




LECTURE I.


Philadelphia is one of the healthiest cities in the United States, and,
in proportion to the number of its inhabitants, few more healthy cities
exist in the world.

This is not owing especially to its more salubrious situation, but
should be attributed, in a great measure, to the accidental superiority
of the ventilation of a large proportion of its dwelling-houses.

Notwithstanding this comparative excellence, the theory of ventilation
is not so thoroughly understood, nor is the practice so perfect, even
in this city, that no advantage can be gained by further knowledge upon
the subject.

Far from it. From the very best information we can command, and with
the most accurate statistics at our disposal, we are forced to the
conclusion that about forty per cent. of all the deaths that are
constantly occurring are due to the influence of foul air.

The Registrar of Records of New York gives nearly half the deaths in
that city as resulting from this cause.

The deaths in this city for 1865, according to the report of the Board
of Health, were seventeen thousand one hundred and sixty-nine; the
average age of those who died was between twenty-three and twenty-four
years. It ought to have been twice that, as shown by some districts in
the city and also in the country, where the houses are so arranged that
they frequently have good ventilation.

Taking the deaths caused by foul air at a very low estimate, say forty
per cent. of the whole, (the per centage from that cause is not so great
as in New York,) we have six thousand eight hundred and sixty-eight
deaths in this city, caused alone by impure air, in one year.

It is estimated by physicians that there are from twenty-five to thirty
days of sickness to every death occurring; there would therefore be
something like two hundred thousand days of sickness annually as an
effect of foul air.

We all know how very expensive sickness is, but few persons realize
the enormous aggregate expense of unnecessary sickness in a city like
Philadelphia.[1]

This subject has awakened much interest in Europe of late years, and
has led to the expenditure of immense sums of money, for the purpose
of improving the sanitary condition of its cities.

Dr. Hutchinson estimated the loss to the city of London, growing out of
preventable deaths and sickness, at twenty millions of dollars annually,
and Mr. Mansfield estimates the loss from this cause to the United
Kingdom at two hundred and fifty millions of dollars.

In the single State of Massachusetts, an estimate exhibits an annual
loss of over sixty millions of dollars by the premature death of persons
over fifteen years of age.

It is estimated that a few only of the principal items of expense
incurred by preventable sickness in the city of New York amount to
over five millions of dollars annually.

And if it is thought that Philadelphia is exempt from such enormous
unnecessary expense, just glance at the report of the Board of Health
for last year, and see how the deaths from disease of the lungs largely
exceed those from any other disease.

Consumption is almost entirely the result of breathing impure air,--it
is as preventable by the exclusive use of pure air as _maniaa potuor_
drunkenness is by the exclusive use of pure water. And see, too, what
slaughter among the innocents--over twenty-five per cent. of the whole
deaths were under one year of age.

The infantile mortality is by many considered the most delicate sanitary
test. But why does such an intelligent community as this so neglect
its own interest?

They have listened to and satisfied the first imperative demands of
nature--shelter from the elements and warmth,--and in doing this they
have not brought into use that much higher order of intellect which can
alone teach them how to supply, in connection with an agreeable warmth,
an abundance of pure air in their otherwise air-tight houses.

