10 March. 1917.] Side'if/lit-< on the 0/ire Oil Imliisiry. 161 



possible. If exposed to \\u- air it becomes rancid more quickly, aiul if 

 p.xposed to liulit th(> plieiiiical rays appear to act on it detriniPiitally. Nvw 

 oil is better than old oil, tbongli many tbiuk tliat old oil, like old wine, is 

 the better. The ])rai-tic'al I bought gained by this knowledge is, to buy 

 just sufficient oil to last froTii one season to another. >rew oil, especially 

 with a little sugar in it, is less nauseous to cliildren, and is more ])alatable 

 to those wbo drink it for gall-stones and other troubles; also, in that 

 state it is more wholesome, and less given to cause digestive troubles. 

 Poured on new bread with a little salt sprinkled over, it is quite palatable. 

 Owing to the general ignorance of the difference between new and old oil, 

 the more general use of olive oil in domestic economy is lessened. Much 

 of the imiKirted oil sold is on the old side, and is frequently adulterated 

 with other oils. 



Continuing the ])rocess of extraetinn, the pressed pulp from the bags, 

 called the marc, is taken out and re-crushed in a Cbillian mill. The 

 stones are in this instance broken. A little warm water is added to the 

 marc to replace the juice previously extracted, and tbe process of 

 extraction goes on similarly as in the first instance. This gives a secoird 

 quality oil which can only be detected from tbe first quality by an epicure. 

 The temperature of the room in which tbe oil is extracted should be 

 warm, otherwise tb(> oil does not flow freely during the extraction. If 

 the room is very cold, the oil extracted has a higher percentage of olein 

 present. 



In large factories the second marc may be again treated as above, 

 or is subjected to the carbon bisulphide process to dissolve out the 

 remaining oil, which is used for lubricating, soap-making, &c. The 

 marc is fed to pigs, or for such purposes mixed with other food. It is 

 apt to scour if fed by itself, owing to the oil present, and to the presence 

 of the broken stones causing an increased peristaltic action on the 

 bowels, and a freer flow of intestinal juices. 



When the marc has been subjected to the carbon bisulphide process 

 it may be sold as manure, as also may the liquid extract from the olives 

 which contains a varying amoimt of potash salts. 



Xo deleterious and un]deasant odours should be jjermeating the 

 building in which the olives are stored, and in which the oil is made ; 

 also when sending "olives to the factory the vessels should be perfectly 

 fresh and clean, otherwise a distinct flavour and odour are given to the 

 oil, and its market value is reduced. 



The amoimt of oil extracted from 1 cwt. of olives varies from just 

 over a gallon to 2 gallons, rarely more, unless the residual oil in the 

 marc is extracted by carbon bisulphide, and as the best olives operated 

 on here contained 44 per cent, of oil, and the lowest about 25 per cent., 

 it follows that by the ordinary lever press used, only 18 i>er cent, to 

 20 per cent, of the oil of the best varieties is extracted. This includes 

 the virgin oil and the second quality oil. With the relatively small 

 quantity of olives operated on at the college, it does not pay to make 

 a third crushing, of by means of carbon bisulphide to extract the re- 

 maining oil from the marc or cake. Where the olive oil industry is on 

 a large scale it pays to extract all the oil, or as much of it as possible. 

 The inferior grade oil could be used for lubricating, soap making, 

 burning, (Sic. I may mention here that a good night light niav be 



1962.— 2 



