Odorless? I Doubt It
In the 1870s, inventors were trying to de-stink the new-fangled
indoor flush toilet.
One design relied on a constant air flow through a ventilating chimney.
Flush toilets were just appearing in homes in the late 1800s.
The ancients had flush toilets as far back as the Indus River Civilization
in 2600 BC, but they disappeared in Europe when the Roman Empire collapsed.
But now they had finally returned, and they were connected
to the new systems of municipal sewage systems.
The good news was that the waste could flow from the home to the sewage system.
The bad news was that sewer gas could enter the home.
The trap seems like the obvious solution today.
This is a segment of pipe shaped like an S
laid on its side when the drain continues downward,
or like a P laid on its side when the drain
continues horizontally into a wall before turning downward.
Water always remains in a 180° segment of a trap,
preventing airflow from the sewer into the home.
Or at least it should.
An article from 1875 says, "It is known, however, that a pressure
of two ounces or less per square inch is sufficient to displace
the water in any trap."
Converting to modern units, that is 8.8 grams per square centimeter.
That pressure would move the water levels by 8.8 cm on either side
of the trap, lowering the sewer side and raising the house side.
Well, sure, that much displacement would cause fœtid air
to bubble back through a typical trap, but...
What was going on in late 19th century sewer systems
to cause air pressure levels that would lift water almost
Scientific American magazine used to be a weekly publication.
You can read old issues at
In the late 1800s it reported on recent patents and projects by and for
home experimenters and tinkerers.
November 20, 1875 issue of Scientific American
contains a report on a new patent for an odorless water closet.
The design relies on a ventilating flue that constantly draws up air
like a chimney.
Air flows down into the toilet, which has a wide-mouthed funnel rather than
the bowl we see today.
The air flow is brisk enough to sweep all, or at least most all,
of the sewer gas along with it, to the side and up the flue.
It's important to note that this sends sewer gas up the flue,
as opposed to flushing the toilet down into the furnace as
by one reader of The American Architect.
a toilet to
I suppose houses were poorly insulated back in the 1870s, so there could
be a constant breeze whistling in under the doors and through cracks and
seams, flowing into the bathroom and down into the toilet.
The picture is above, let's see the description from the magazine text:
IMPROVED ODORLESS WATER CLOSET
It is just now beginning to be understood that the results
of defective drainage are pestilence and death, and, moreover,
that many of the safeguards, hitherto relied upon as protections,
are in fact no defense whatever.
Into the public sewers all kinds of excrementitious matters,
waste, and offal, are deposited, along with abundance of water,
and the whole is exposed to a temperature favorable to fermentation.
The offensive sewer gas is the product, which seeks to escape
from its confinement in the sewer by every practicable outlet.
The only protection against this escape, commonly employed,
is the water-sealed trap, usually in the form of an S,
the lower bend of which is supposed to be constantly filled with water,
and to prevent the passage of sewer gas.
It is known, however, that a pressure of two ounces or less per square
inch is sufficient to displace the water in any trap,
and this small pressure is frequently exceeded by the gases
confined in the pipes.
Such augmented pressure may be produced by the influx of a stream of water,
by the variation of temperature caused by the entrance of hot water,
by wind blowing into the open mouth of the sewer,
or by the backing in of tide water, by flushing, etc.
In addition to these are other causes capable of unsealing traps,
as the disturbances of pneumatic pressure in flushing
some distant part of the pipe,
siphoning by portions of some textile fabric,
as a cord, string, or rag washed partly out of the trap,
The presence of the characteristic smell in the vicinity of a water-closet
denotes that some one of these causes is at work,
forcing or aiding the escape of the gas from the opening of the waste pipes.
Traps are designed to suppress and keep in confinement the gaseous products
of sewer decomposition.
We have repeatedly pointed out, however, the defects of the trap system,
and have also expressed the opinion that the best precaution
is found in properly directed ventilation,
by which the noxious exhalations will be harmlessly carried away.
We are therefore able to pronounce favorably upon the invention
herewith illustrated, which is based upon the ventilating
principle, and in which the bowl of the water closet is directly connected
with a chimney or other flue, through which a draft of air will be caused
to flow upward and be discharged above the house top.
It will be perceived that this arrangement merely constitutes a siphon,
the long leg of which is the flue and the short leg the bowl of the
water-closet, and that the well known siphon action must ensue.
The effect, we are informed, is a complete and perfect prevention of
the escape into the apartment of any gas or odor from the soil pipe
or interior of the container.
This effect is well represented by the arrows in the engraving,
the regular ones denoting the flow of pure air, and the crooked
ones denoting sewer gas or foul smells.
With these closets traps may be advantageously dispensed with,
because whatever sewer gas comes to the containe will go up the chimney
instead of into the apartment, and its presence is immaterial.
Besides, with a free outlet of escape at every closet,
there could be no accumulation of such gas, and the work of
disposing of it would be constantly going on.
These closets are in successful use in the cities of Washington, Baltimore,
Cincinnati. Chicago, and elsewhere, and in no instance
have they failed to give entire satisfaction.
The inventor guarantees them to be perfectly odorless
in every instance, if properly set.
With reference to the liability of a down draft in the chimney to cause
an overflow of gas, the inventor says that he has not yet encountered
any such effect in a well constructed chimney
into which air could enter anywhere below the top,
and that if the chimney does not draw properly it is simply
a case for correction, and must be made to draw.
There are also several minor points of improvement worth noticing.
The container is placed upon legs, which gives the plumber access
to the soil pipe joint, and enables him to caulk it tightly without trouble.
The cover is fitted with a rib entering a groove in the rim,
so as to insure a tight joint there, with but little material.
The bowl is bedded in putty or cement under the flange and down
beside the neck for an inch or more, which insures for it a very firm seat.
Patents for this invention have been granted to
R. D. O. Smith, 613 Seventh Street, Washington, D. C.,
to whom inquiries for further information should be addressed.