BY-PRODUCTS FROM ASCLEPIAS AND APOCYNUM. 59 



Experiment 2. 



A quantity of milkweed stalks, selected as described in Experiment 1, 

 was boiled in an open kettle with water for 8 hours. Softened stalks were 

 crushed in wringer as above described. Then furnished to autoclave, where 

 they were cooked with 10 per cent caustic soda for 8 hours at 30 pounds 

 pressure. The cooked material was washed, beaten, and run out into hand 

 sheets. The yield from material as received to bone-dry paper, unbleached, 

 is 40 per cent. 



The paper resulting from this experiment was highly satisfactory; quite as 

 satisfactory as that obtained from Experiment 1, and obtained in a much 

 less expensive manner. 



It was thought by cooking with lime a paper of equally soft, pliable quality 

 might be obtained. The result of this attempt we report under Experiment 3. 



Experiment 3. 



A quantity of selected milkweed stalks was boiled in water for 8 hours, 

 crushed in the wringer, and cooked in the autoclave with 10 per cent lime 

 for 8 hours, at 30 pounds pressure. Cooked stock was washed clean and 

 beaten, then run out in hand molds as sheets of paper. 



Yield from material as received to bone-dry paper 42 per cent. 



The resulting paper from Experiment 3 was much inferior in softness and 

 pliabiUty to that obtained in either Experiment 1 or 2, although the yield 

 from material as received to unbleached paper was the highest reported. 

 It is, however, relatively free from harsh, incrusted, shivey particles. Paper 

 obtained from Experiments 1 and 2 was entirely free from harsh, shivey 

 particles. 



The lime used in these experiments was a good grade of hydrated 

 lime, containing about 95 per cent calcium hydrate, 1.3 per cent 

 impurities (silicon dioxide, iron, and alumina). The caustic soda was 

 good grade 58 Solvay process caustic. 



The resulting fibers, as obtained from sheets of paper made in Exper- 

 ments 1 and 2, have many of the characteristics of linen. They are 

 long and silky, possessing remarkable strength for the type of material 

 from which they are obtained. 



It is of interest to note that this material does not yield readily to 

 bleaching with calcium hypochlorite. It may, however, yield more 

 readily to bleaching with hypochlorous acid or possibly sodium hypo- 

 chlorite. 



For material of this type, yields for material as received to un- 

 bleached paper in all cases are exceptionally high. 



An interesting note is made by the laboratory expert that very- 

 likely in the process of extracting rubber the raw material may be 

 put through a breaking-up process which would so separate the woody, 

 fibrous, and pithy components as to render unnecessary the pre- 

 liminary cook with caustic soda. The paper-maker therefore would 

 start with the lime cook, thus saving the prohibitive cost of reduction 

 by caustic and crushing. 



This matter has been taken up also with a director of a scientific 

 laboratory connected with one of the large rubber factories, and he is 



