﻿FISH-SCRAP FERTILIZER INDUSTRY OF ATLANTIC COAST. 



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strictly between menhaden oil and other so-called fish oils, such as 

 those obtained from the whale, porpoise, and seals, as those from the 

 latter three sources lack those qualities possessed by menhaden oil 

 to a marked degree, which would classify them as drying oils. Their 

 admixture with drying oils, such as tung and boiled linseed oils, 

 does not avail, for while they may appear to have dried they become 

 sticky again in the presence of humid air. 



In the subjoined table are given the specific gravities and iodine 

 numbers of several oils commonly classed as fish oils. The iodine 

 numbers are determined by the method of Hubl. 



Table XIV. — Specific gravities and iodine numbers of fish oils. 



Kind of oil. 



No. 1. Crude whale oil . . 

 No. 1. Filtered whale oil 

 No. 2. Filtered whale oil 



Cod oil 



Porpoise body oil 



Seal oil, water white 



Specific 





gravity 

 at 20° C. 



number. 



0.91% 



136.1 



.9168 



125.0 



.9187 



142.9 



.9196 



147.3 



.9233 



132.3 



.9227 



143.0 



Kind of oil. 



Menhaden oils: 



Extra bleached winler 

 Bleached, refined 



Regular 



Dark brown 



Specific 

 gravity 

 at 20° C. 



0. 9237 

 .9273 

 .9249 

 .9250 



Iodine 

 number. 



150.4 

 161.2 

 165. 7 

 154. 5 



The authority quoted says further : 



The oil that gives the best and most lasting results for paint purposes is the 

 menhaden oil, and the winter-bleached variety is the one that should be rec- 

 ommended. This is an oil fairly pale in color, with an iodine number of 150 

 or over, and with little or no fishy odor ; in fact, I might say that in the pur- 

 chasing of fish oils for paint purposes it is well to beware of a fish oil that has 

 the so-called characteristic fishy odor. I have not yet satisfied myself as to the 

 cause of this odor, but, so far as I have reached in my investigation, I am 

 inclined to believe it is due to phosphorous decomposition compounds. The re- 

 sults which I have obtained from the proper grades of fish oil — and I am glad to 

 say that there are several manufacturers sufficiently intelligent to market the 

 oils that are very desirable — warrant me in saying that fish oil in the hands 

 of an intelligent manufacturer, and used up to 75 per cent, produces excellent 

 results for exterior purposes. For interior purposes fish oil does not seem to 

 be desirable, for it gives off noxious gases for a long time. 1 



It is recommended that for exterior work three parts of fish oil be 

 mixed with one part of linseed oil. The mixture is nonhygroscopic — • 

 when dry it remains dry — and the results obtained with it are de- 

 scribed as excellent and lasting. The iodine number, it is main- 

 tained, is an index of the suitability of fish oils for paint purposes. 

 It profitably may be substituted for linseed oil in a number of appli- 

 cations. It is more resistant to the action of heat than linseed oil, 

 and hence is especially adaptable to use in painting ironwork such 

 as boiler fronts and smokestacks. It holds up better in a moist cli- 

 mate, such as that existing in proximity to the seashore. Its use is 



1 Toch, loc. cit. 



