INFLUENCE OF RELATIVE HUMIDITY AND MOISTURE CONTENT. 9 
moisture content of the flour produced was 12 per cent, and at 65 to 
69 per cent relative humidity, the moisture content was 13.3 per cent, 
or an increase of 1.3 per cent moisture for a difference of 30 per cent 
in relative humidity. 
It has been suggested that probably these are the normal moisture 
contents for flour at the respective relative humidities shown, but 
such a conclusion is not entirely justified, for the reason that in these 
tests no proof exists that the exposure of the flour to the air, which 
was limited to the length of time necessary for milling the sample, 
was sufficient^ long to establish a state of equilibrium between the 
moisture content of the flour and that of the mill atmosphere. On 
the other hand, proof that at least some of these moisture contents 
are not normal is evidenced by the wide divergence from the results 
obtained by Bailey, to which reference has been previously made. 
For instance, he found that the hygroscopic moisture in flour in 
equilibrium with atmospheric humidity at 25° C. ranges from a little 
more than 5 per cent at 30 per cent relative humidity to 15 per cent 
at 60 per cent relative humidity. 
COMPARISON OF THE INFLUENCE OF RELATIVE HUMIDITY AND 
OF MOISTURE CONTENT OF WHEAT ON THE MOISTURE CON- 
TENT OF FLOUR. 
Some indication of the comparative influence exerted on the mois- 
ture content of flour by each of the factors, atmospheric humidity and 
moisture content of the wheat before tempering, is given in figure 5. 
In this figure the results from samples which before tempering had 
moisture contents falling within various ranges are represented by 
separate curves. From this system of grouping it is possible to ascer- 
tain the particular influence exerted by each of these two factors. 
The proximity of the four curves to each other and their tendency 
to cross and recross each other indicate, for the method of tempering 
used in these experiments, no very pronounced relation between the 
moisture content of the 'flour and the moisture content of the wheat 
before tempering; or, in other words, no relation to the quantity of 
temper water added. On the other hand, a decided tendency is shown 
for the moisture content to increase as the relative humidity increases, 
a difference of 10 per cent in relative humidity making an average 
difference of approximately one-half of 1 per cent in the moisture 
content of the flour. 
It would be interesting to know what influence, if any, variations 
in the final moisture content to which wheat may be tempered and the 
length of the tempering period would have on the resultant moisture 
content of the flour milled at different relative humidities. Since all 
samples were tempered to the same moisture content and for approxi- 
mately the same length of time, it is impossible to draw any conclu- 
sions in regard to this influence from the results of these experiments. 
