ere
puzzles me. Certainly had I been permitted to see a proof of that
paper the mistake would have been corrected, unimportant as it is, so
far as Barye is concerned. I must compliment your correspondent on the
quickness of eye that detected the slip and regret that the
proof-reader of _Harper's Weekly_ did not know his Baltimore to the
same degree. But he is himself in error when he speaks of the "_Life
and Works of Antoine Louis Barye_," written by me and published by the
Barye Monument Association as a catalogue. The catalogue is quite
another thing from the _edition deluxe_, which is the only edition of
the "_Life_."

CHARLES DE KAY.

EVAPORATION OF WATER IN TRAPS.

TO THE EDITORS OF THE AMERICAN ARCHITECT:--

_Dear Sirs,_--In a late issue of your journal an advocate of
Trap-venting, says of ordinary S-traps "If the traps are filled even
once in two months they will keep their seals intact."

Most persons now agree that S-traps which are back-vented in the
ordinary manner require refilling by hand as often as once a
fortnight. It is, therefore, clear that the system of back-venting is
a very dangerous one. Its original object was to afford security. It
is now found (and strangely enough, even by its advocates) that it
totally fails in this respect and that it requires an amount of
attention which experience and common-sense show us it will never
receive.

My experiments on the rate of seal-reduction through evaporation
produced by back-venting were made with the greatest care and show a
more rapid loss than is generally supposed. If the reports of these
experiments are studied, it will be seen that every precaution was
taken to secure trustworthy results. Although my experiments on
siphonage were made during the same year and on the same system of
piping with those on evaporation, it will be seen by studying the
drawings and text of the report that the former in no wise interfered
with the latter. No experiments on siphonage were made while the water
stood high in the traps during the tests for evaporation, and no
disturbance of the water seals was made by this or any other cause
during the evaporation tests. It would have been exceedingly careless
and totally unnecessary to allow of any such disturbance. Moreover,
most of the experiments on evaporation were made, as shown, on a stack
so connected with the rest of the system of piping that such
disturbance would have been impossible. Even had we not s