14 EXPERIMENT STATION RECORD. 



with drying properties, comparative tests with linseed oil were made. Both 

 oils were heated and treated with lead oxid and heat, and with manganese 

 dioxid and heat. Some tests with raw oil were also made. 



The raw oils absorbed oxygen slowly, and the percentage increase was a 

 little greater in the case of linseed oil. Both films of oil were dry but gelatin- 

 ous, the raisin oil being a trifle more sticky The heated oils absorbed oxygen 

 much more quickly than the raw oils. " The increase was steady and con- 

 siderably more rapid than in the raw oils, the maximum in both oils being 

 reached in 216 hours. The i>ercentage of absorption was practically the same 

 as in the raw oils, but the time of absorption was less in the raisin-seed oil, 

 the heating, therefore, having the effect of hastening the drying. 



" The experiments show also that by heating the oils with lead oxid in quan- 

 tities varying from 0.5 to 4 per cent, oxygen was absorbed with much greater 

 rapidity than by the heated or raw oils. When heated with 1 and 2 per cent 

 of lead oxid, the films had practically become set In 6 hours, the absorption 

 in raisin-seed oil amounting to 5.1 and 5.7 per cent, respectively, and in linseed 

 oil to 7.8 and 9.3 per cent, respectively. . . . The maximum absorption in the 

 case of raisin-seed oil was 8.1 to 9.12 per cent, and in linseed oil 12.2 to 13.7 

 per cent, which was about the same range. . . . Manganese dioxid seemed to 

 be much less efficient as a drier than the lead oxid, the length of time necessary 

 to dry the films being in all cases considerably longer than when the oils were 

 heated with lead oxid. . . . Taking into consideration the ready-drying prop- 

 erty of raisin-seed oil, especially when treated with an ordinary drier such 

 as lead oxid, it should be of value in the paint and varnish industries." The 

 experiments bear this out. " Raisin-seed oil is decidedly resistant to heat and 

 declines to take on color even when heated to 500° F., whereas linseed oil 

 darkens considerably and takes on a greenish color. The somewhat slower 

 drying properties of raisin-seed oil should not be especially detrimental to its 

 usefulness, since this can doubtless be overcome by treatment of the raw oil 

 with proper driers." 



The tests conducted also show that the oil may eventually find a place in the 

 soap industry. 



"After the preparation of the sirup and the extraction of the oil from the 

 seeds, the extraction of tannin has been recommended. The production of 

 tannin extract is practicable only in the case of raisin seeds, since wine residues 

 are probably largely depicted of their tannin content. The tannin, being soluble 

 in water, can be extracted in a practical way by boiling the meal in large diges- 

 tion vats, the solution being transferred to vacuum pans for concentration to a 

 moist extract. If a dry extract is preferred it can be obtained by simply allow- 

 ing the moist extract to dry in the air. The large quantity of tanning extract 

 which can be produced from raisin-seed meal, and which is well adapted for 

 the tanning of leather, becomes the third important commercial product capable 

 of being made from raisin seeds." 



The final residue, termed the meal, gave on analysis 10.6 per cent of moisture, 

 12.12 per cent of protein, 1.2 per cent of ether extract, 30.5 per cent of nitrogen- 

 free extract, 43.2 per cent of crude fiber, and 2.4 per cent of ash. On account 

 of its comparatively high protein content, it is suggested that it should be use- 

 ful as a stock feed. 



METEOROLOGY— WATER. 



A method of approximating rainfall over long periods and some results 

 of its application, A. E. Douglass {Science, n. ser., 37 (1913), No. 9JfO, p. 

 S3). — " It was found by a test extending over 43 years that the radial thickness 

 of the rings of the yellow pine of northern Arizona gives a measure of the rain 



