REPORT OF THE CHEMIST 159 



SESSIONAL PAPER No. 16 



they would be classified as ' coarse,' and wovdd receive a lower valuation for nitrooen 

 and phosphoric acid than if finer. For direct application, as by farmers, grinding 

 would notj perhaps, bo necessary. 



A ncdysis. 



No. 2. No. 3. 



Dos-fish Dog-fish 



(wood dried), (coal dried). 



Moisture 1490 1218 



NitroR-en 7-5!) 7-63 



Phosphoric acid 2-94 2-90 



Total mineral matter 7-05 T-29 



Mineral matter insoluble in acid (sand) 16 -43 



Oil 31-47 32-75 



The percentage of nitrogen in these scraps is very satisfactory. The very low 

 percentage of phosphoric acid is due to the fact that the dog-fish has not a 'bony' 

 skeleton but belongs to a group of fishes (the Selachians) in which cartilage very 

 largely replaces phosphates of lime. 



Both these scraps possess very high percentages of oil. Oil is not plant food ami 

 its presence in excessive amounts prevents the decay of the scrap in the oil, and hence 

 retards the liberation of its plant food constituents in available forms. Further, the 

 continued and excessive application of a fertilizer so rich in oil might work serious 

 injury to the proper physical condition of the soil. Possibly some modification in 

 the process of manufacture may be devised whereby a larger portion of the oil may 

 be removed. Whether a further extraction of oil from the scrap by naphtha (gaso- 

 line) could be made, without entailing undue expense, I am at present unable to say, 

 but my opinion is that from the agricultural standpoint it is highly desirable that a 

 scrap poorer in oil be prepared. 



The analysis of the fourth sam]ile of dog-fish scrap, forwarded November 11, 

 1905, furnished the following data : — 



Moisture 20-28 



Nitrogen. . . 7-95 



Phosphoric acid 2-36 



Total mineral matter 6-71 



Mineral matter insoluble in acid (sand, &c.) -35 



Oil 28-49 



This sample is not so dry as those received on October 3. In nitrogen it is a 

 little richer, but in phosphoric acid it is somewhat lower, pointing to a slightly larger 

 proportion of flesh, cartilage, &c., and concomitantly less bone than in the former 

 samples. Presumably it is entriely the refuse from dog-fish. 



Although it was stated that the livers were excluded when making this scrap, the 

 amount of oil present does not fall far below that in the scraps previously examined. 



• 

 Fish-scrap Liquor. 



In the preparation of the scrap a considerable amount of liquor is expressed from 

 the cooked dog-fish which after yielding the greater part of its oil is allowed to run 

 to waste. To learn what fertilizer value this liquor might possess a sample forward- 

 ed in January, 1906, was submitted to analysis and the following results obtained: 



Drv matter 1119 



Water 88-81 



10000 



Ash.. 103 



Nitrogen ' 1-69 



Oil 4-33 



