

270 REPORT OF THE CHEMIST OF THE 
makers may make use of these tables, if they wish to pay atten- | 3 
tion to the amount of moisture in curing rooms, it has been — 
thought desirable to present them here. In Fleischmann’s work, 
the tables are given for centigrade scale; we shall give them for 
both centigrade and Fahrenheit scales. 
The hygrometer and the principle of its use have already been 
mentioned. Weshall here make some additional statements regard- 
ing the details of its use, especially in connection with the Latte 
given. 
I. How to Find the Amount of Moisture in Air. 
Take the reading of the dry-bulb thermometer and the reading 
of the wet-bulb thermometer. Subtract the latter from the for- 
mer. Then turn to tables and find column which contains the 
difference found between the two thermometers or the number 
nearest it. Then follow down this column until the figure is 
found opposite the number in the left hand column which is the 
same as the temperature indicated by the dry-bulb thermometer. 
The number thus found indicates the relative amount of moisture 
in the air or how much moisture the air actually holds compared 
with what it would hold at that temperature if saturated. This 
statement can be made clearer by an illustration. Suppose that 
we find the reading on the two thermometers as follows: 
—_ ———. —_ —-- -—-- + 
FePE UL LOSTINOMGEL. 1.55.00 ce adpbosexpaiassudede apes oe CULE Rae tase Sete ae Oks 14, 6° He (58.8° F.) 
WV GtsDUL CHOPMOMEOELEL ;.. 0 gee slco daiwa vCRs p Miatwebe Sieh alow Abie ba aulen Baie auetiiees 18.4° C eh: Los, ED 
MPEP OP ETICE: Fe aiaiicdiovs ae» 46,40 aroteqetatale'a dang win Patauntera Ooh Wie eUheca uate tlc leroy ete isle va Glaoiere nTehars Rk "20 2° C, Q. 2 2° F.) *" 


We turn to the tables and look in the upper horizontal row 
(printed in heavy-faced type) for 1.2° CO. (or 2.2° F.). Having 
found this number we run down the column until we come oppo- 
site tha number indicated by the dry-bulb thermometer, 14.6° C. 
(or 58.3° F.) in the two vertical columns at the left (printed in 
_heavy-faced type). This brings us to the figure eighty-six, which 
indicates the relative amount of moisture in the air; inother 
words, the air contains eighty-six per cent as much moisture as it 
can hold at this temperature (14.6° C. or 68.3° F.). To take 
another example: ; . 
(66 2° F.) 


SV ls thErMOMELSL vi5.cs oss seks ov ee CAMA bee NaR chau seem mene asia eels 19° C, 
WV Ot DULD THErMoOmMeter cs. i eicadine sree ce ak oa mick Reis aalenave Ook omens wide d aire 15°°O, (9 0crne) 
Ptrarehine sible sie ced hae ne Eos i ee Rt cRree er 490. (7.2° BD 




Reference to tables shows that the air contains sixty- wo per. te 
cent of all the moisture it is capable of holding at the tempera- ee 
ture of 19° C. (or 66.2° F.). 

