Evening star. [volume] (Washington, D.C.) 1854-1972, 1885-03-07
CITY AND DISTRICT.

ANALYSES OF AIR IN TWO sT-cF4 BI-IYDT~GS
District Chemist De Snedt, in compliance
with verbal direction of the District Commits
sioners. has made an analysis of the air in the
"Twining' and "Banneker'' school buildings
and states, in his report. that on the 18th
instant ne made some tests in both these build
iIlS>, which lead him To the following conclu-
sioAS a. 70 the normal condition Of the air there
IN: Inc tests in the Twining building were in
scnoot No -. on The third floor, containing 56
white children. those in the Bannellcr building
were made IL school No. I. on the second door,
containing % coiored children. On the 2oth
instant he returned T. the Twinng building
IN orneT To make cumulative analysis OF the
hlF- me process IolI wed was fhat laid down
by ISoussfgnault based upon The absorption of
carDOhic acid by caustc pOja D. ana # moi sturC
by strong sulphuric acid. and finally the alb
sorptiOn of oxygen by COPPER etc The results
of these analyses taking the air from various
heights in the BanueLer school Ly weight are
as follows: CarbOnic acid 900 O:;: oxygen %. 90:
In the Twtning school. room 40. 9. carUonic
acid, 900 oxygen. - -. II is therefore
Guided that The air in the Twiniug school is OF
normal condition, which il attributable To good
ventilation of the rooms \ person requires
~ sooul ~ CUBIC leet OF air per hour W hen in
the act OF breathing tn" oxygen partly unites
with carbon in the system and the air'exhalcd
contains 4l2 per cent OF carbonic acid. This i'm
medlately disperses through the atmosphere 10y
the property Of diffusibilirv. possessed in such a
remarkable degree by the gases Ii. however. it
Is confined within close place. il soon acculnu-
lates and contaminateS the air The pbrno,nena
Of respiration and the effects of com buStion pro-
luce continually great mass of carbOnic acid
atmosphere. 1t might. therefore. he supposed
that the oxygen must keep on diminishing. and
that at certain period the atmospheric air be-
comes contaminated with carbonic acid: but by
virtue of the great natural haTuonicS which
unite the animal domain with the vegetable il
Is observed that while the animal operates like
combustion apparatus, fixing the oxygen OF
the air and eXPelling it in the state of carbonic
acid, the plant plays the reverse part. operat-
ing as reducing apparatus. Under the infiu-
ence of solar light carbOnic acid is ali
sorbed by the plant and decomposed: ear
bon is retained. and pure oxygen is restifuted
70 the atmospheric air. The acid contaminated
by animal life is purified by vegetable life:
hence the great harmonic anu constant compO-
sitlon of the atmospheric normal air. The
atmospheric air which is brought in a large
volume by the heating apparatus from outside
into these buildings. and the not air OF the rooms
hndtng an outlet into cold cOndutS effects q
CONSTANT renewal of air. Herein lies the secret
of the small quantity OF carbunic acid found in
the rooms ventilated. Relying on numerous
experiences Of this nature. we therefore 0:ttur-
ally come to TIE conclusion that the Saiubrity
OF atmospheric air can be determined by the
quantity Of car3Onic acid found in rooms or
buildings occupied by many persons, which in
dIcateS the utility of a renewal OF fresh normal
ar more or less active, without attTibuti1G to
c1rbontc acid alone the unhealthy effects of
remaining long in confined air. Ia the Banneker
school, room I, occupied by 81 coiored children
and teacher, there carUOnic acid, 600. O4:
oxygen, -. 9S per cent.