FISH-NET PRESERVATIVES. 53 



LINSEED OIL. 



Tests made were on cotton waste treated with the various preserva- 

 tives studied. Two other tests were made upon samples of cotton 

 waste that had been treated with hnseed oil. Spontaneous heating 

 is perhaps more likely to occur in the presence of linseed oil than of 

 almost any other common substance. The tests with it were made, 

 therefore, for the purpose of determining whether or not spontaneous 

 heating would actually occur under the conditions set up for the 

 experiments. 



Twenty grams of cotton waste was moistened with 25 cc. of linseed 

 oil and the waste allowed to dry somewhat and placed in the tester. 

 The water was brought to boiling and the temperature of t and t' noted. 

 Tlie maximum temperature recorded by t was about 203° F. (95° C). 

 The temperature oi the waste, shown by the thermometer t, rose at 

 about the same rate as that of the surrounding air, shown by t' . When 

 a temperature of 212° F. (100° C.) was reached, readings were made at 

 intervals of one minute. The temperature rose 1, 1^, and 2° per 

 minute up to about 266° F. (130° C.), when the differences became 

 gradually larger, reaching a maximum between 300 and 345° F. (149 

 and 174° C), when the differences were 14° F. (8° C.) per minute. 

 The increments per minute then became gradually smaller, and a 

 brown gas or smoke was noticeable above 368° F. (187° C). The 

 maximum temperature obtained in this experiment was 419° F. (215° 

 C). The waste was scorched to a brov/n color. The experiment 

 with linseed oil was repeated with the same results as described in 

 the preceding paragraph. 



A third test with linseed oil was made but differed from the first 

 two in that the temperature of the water in the outer jacket was 

 maintained at 122° F. (50° C.) instead of 212° F. (100° C). This 

 temperature was held for about four hours, but the temperature of 

 the waste saturated with linseed oil did not rise above that of the air 

 surrounding it — about 113° F. (45° C). It may therefore be con- 

 cluded that a temperature higher than this is necessary to kindle 

 spontaneous heating of linseed oil. 



COPPER OLEATE. 



A sample of copper oleate taken from the batch before it was 

 blown was dissolved in benzol. Cotton waste was saturated with this 

 benzol solution and allowed to dry, after which it was placed in the 

 tester and the temperature of the water in the outer jacket brought 

 to 212° F. (100° C). This temperature was maintained for a period 

 of three hours. The maximum temperature reached in the inner 

 chamber was 194° F. (90° C). The maximum temperature of the 

 waste was also 194° F. (90° C), proving that there was no elevation 

 of temperature in the waste caused by the unoxidized copper oleate. 

 This experiment was repeated under like conditions and the same 

 results obtained as in the first case. Two other samples of waste 

 that had been saturated with a benzol solution of the finished or 

 oxidized copper oleate were tested in the same manner as described 

 for the unoxidized samples. The maximum temperature obtained 

 in each of these was 194 F. (90° C), both in the sample of waste and 

 in the air surrounding it. 



