170 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Processes em])loyed in manufacture. 



238. The process of oil-making at the larger works is essentially as fol- 

 lows : The fish are conveyed to the upper story of the factory on wooden 

 tramways in cars coutaiuiug about twenty barrels each, and are dumped 

 into large reservoirs from which the cookiugtauks are replenished from 

 time to time, or are emptied directly into the cooking-tanks, .which are 

 filled to the depth of six inches with sea-water. From fifty to seventy- 

 five barrels are placed in each cooking-tank, and then steam is turned on 

 and they are boiled for half an hour or more. In this way about two- 

 thirds of the oil is separated ; the remainder is expressed by means of the 

 hydraulic presses, under a pressure of 50 to loO tons or less ; the fish hav- 

 ing been placed in circular curbs of half-inch iron, perforated with holes 

 an eighth of an inch in diameter, each curb having a capacity of three 

 to ten barrels. The oil mixed with water is now run into the " drawing- 

 off tanks" while it is still hot, and is passed through several of them, 

 the water separating and sinking to the bottom. The oil is now drawn 

 off into a " settling-tank" of four or five thousand gallons capacity, where 

 it remains a few hours to allow impurities to sink to the bottom. Finally, 

 it is pumped into " bleaching-tanks" (of which Judsou, Tarr & Co. have 

 five, each containing four thousand gallons), where it becomes clearer 

 and whiter in the rays of the sun, and after one or two weeks' exposure 

 is ready for shipment. 



Processes enq^loyed in refilling. 



239. Boardman & Atkins make the following statements about proc- 

 esses of refining : 



"The oil and water runniug together into the receivers, separate, by 

 the oil rising to the top, whence it can be drawn or skimmed off. Great 

 pains must be taken to separate the oil from the water before the impu- 

 rities contained in the latter begin to ferment, for if this happens the 

 quality of the oil suffers much. Moreover, in what appears at first to 

 be pure oil there is a variable amount of finely divided fleshy substance 

 that must be allowed to eettle, as it will after a while, and the clarified 

 oil drawn off before putrefaction sets in. In order to effect the separa- 

 tion, the oil is commonly passed through a number of settling- vats, and 

 a portion of the impurities deposited in each, and finally before barreling, 

 the oil is, if practicable, exposed some hours to the sunlight in a broad, 

 shallow tank. If all these processes are successfully carried through, 

 the oil is light-colored, sweet, and of prime quality ; but if it is exposed 

 at any time to the influence of putrefying animal matter, it becomes dark 

 and ' strong.' The very strongest of oil is made from the ' gurry ' or set- 

 tlings of the oil, after fermentation, by steaming or boiling it over. 



" It naturally happens that every manufacturer makes several grades 

 of oil, of very different quality, of which the best is very sweet, fine oil, 

 bringing ten cents a gallon more than a strong article. Notwithstand- 



