24 



BULLETIN 150, U. S. DEPAKTMENT OF AGPJCULTUEE. 



Table VII. — The results reported in Table VI, recalculated to the water-free 



basis. 



Character of sample. 



Nitrogen. 



Phos- 

 phoric 

 acid. 



Bone 

 phos- 

 phate 

 Ca 3 (P0 4 ) 2 



Oil. 





Per cent. 

 11.76 

 7.20 

 8.46 



Per cent. 

 3.44 



4. IS 

 5.9S 



Per cent. 

 7.50 

 9.13 

 13. 06 



Per cent. 

 10.16 





37.22 





30.37 







Average 



8.65 



4.44 



9.70 



28.74 



The value representing the average composition of cannery waste 

 is arrived at by adding the figures for the percentage composition 

 of the heads, taken twice, and of the roe and the fins and tails. The 

 values for the heads are multiplied by two, because, as it will be 

 remembered, the heads are estimated to make up 50 per cent of the 

 waste; while the roe and the fins, with the tails, are estimated to 

 constitute 25 per cent each. 



From this table it appears that the heads are richer in oil than 

 the other parts of the waste. This is to be expected, and agrees 

 with the facts as established practically in the rendering plants 

 operating on this material. The nitrogen content of the heads is 

 correspondingly low. As it is the oil which constitutes the greatest 

 value among the substances recovered, this fact makes the heads 

 the most valuable part. The high nitrogen content of the roe is 

 to be expected, as it is made up to such a large extent of albuminous 

 compounds. Its low content in oil likewise conforms to one's pre- 

 conceived ideas. 



On the basis of the analysis reported in Table VI, the value of 

 the raw cannery waste may be computed. 



The percentage of nitrogen, 3-. 02, is equivalent to 3.67 per cent 

 ammonia, JSTH 3 . This, in the retail market, may be expected to 

 bring $3.20 per unit (a unit being 1 per cent) ; bone phosphates is 

 valued at 10 cents per unit; and oil at 30 cents per gallon. Then: 



3.67 per cent NH 5 , at $3.20 per unit $11. 74 



3.46 per cent bone phosphate, at 10 cents per unit 0. 34 



27.05 gallons oil, at 30 cents per gallon 8. 12 



Total value per raw ton 20.20 



By present methods the manufacturers of fertilizer and oil from 

 this material expect to recover about $15 in values. Present 

 methods, then, can be considered as only 75 per cent efficient. In 

 further substantiation of this conclusion are the results published 

 by Thomas. 1 



1 A. M. Thomas, Waste in Salmon Canning Industry. Pacific Fisherman, 12, No. 2, 26 

 (1814). 



