in 
18 BULLETIN 1389, U. S. DEPARTMENT OF AGRICULTURE 
EFFECT OF DETERIORATION ON CHEMICAL COMPOSITION 
The chemical composition of the samples from the various packers 
(Table 4) was uniform. No connection between the rate of decom- 
position and the composition of the samples is indicated. 
The determination of available chlorine and chloride chlorine at the — 
beginning and at the end of the storage period showed that nearly — 
all of the available chlorine was converted into chloride and that very 
little was lost by volatilization. There were evidences of a small loss 
in most cases, however, the losses being most pronounced in summer- 
packed samples from packers C and D. These samples showed the 
greatest losses of available chlorine, as well as the greatest losses in 
actual chlorine. 
SUMMARY 
The available chlorine in most'samples of bleaching powder packed 
in containers of the usual commercial types decreased fairly regu- 
larly during storage. Most of the available chlorine lost was trans- 
formed into chloride chlorme, the loss in total chlorine in most cases 
and the change in chlorate chlorine being very slight. 
There was no marked difference in the rate of deterioration between 
the samples manufactured and packed in the winter and those manu- 
factured and packed in the summer. There was, however, a sea- 
sonal variation, the loss of available chlorine being greater in warm 
than in cold weather. 
In general, the keeping qualities of the bleaching powder were 
not greatly affected by the type and size of commercial container. 
There appeared to be a small difference in favor of the larger metal 
containers over the other commercial packages. The material 
stored in tightly stoppered glass bottles deteriorated slightly less 
than that stored in cans. 
Two of the samples of bleaching powder packed in the summer 
showed about the same rate of deterioration as the others for the 
first nine months. After that the rate of deterioration increased 
rapidly and was accompanied by a decided increase in the moisture 
content. This may indicate that the absorption of water catalyzes 
the change. 
The results on the rate of deterioration as affected by the method 
of packing did not lead to any definite conclusions. The hand- 
tacked material put up in the summer showed a high rate of loss 
after about 10 months. As one of the machine-packed samples 
also showed a high rate of loss during the same time, however, this | 
can not definitely be attributed to the method of packing. 
The visible rays of light seem to have a slight accelerating effect 
on the loss of available chlorine. 
The average loss in available chlorine for all samples from the 
different sources, packed and stored in various ways, was 1.08 per 
cent per month for the period covered, 12 to 15 months, the average 
for the hottest months (May 15 to September 15) being 1.44 per 
cent per month and for the coldest months (November 15 to March 
15) 0.61 per cent per month. 
