468 FOODS AND FOOD ADULTERANTS. 



particles on the sides of the dish and the liquid became almost colorless 

 again. 



WARREN'S CULORIDE OF SULPHUR TEST. 



The method of investigation employed was the one described by 

 Warren.* It is as follows :] 



Five grams of the oil or mixture are weighed in a tared porcelain dish, which is 

 well glazed both inside and out; it should have a capacity of about 4 ounces, so as to 

 avoid loss from spitting. It should not be covered. Two cubic centimeters carbon 

 disulphide are stirred in and 2cc of the mixture of sulphur chloride added. It is now 

 placed on a hot water bath and well stirred until the actiou is fairly commenced; 

 Avhcn solidified it is placed in a warm chamber, so as to drive off all volatile products. 

 When two successive weighings are the same, it is ready for further operation. The 

 mass will require breaking up, so as to allow imprisoned vapors to escape. 



The color and consistency at the end of the reaction and when subsequently dried 

 should be noticed ; it is now ground up or divided as much as possible. The product 

 may be too tough to break easily, or, if soft and sticky, a portion of the unaltered 

 oil should be removed first. 



It is transferred to a filter tube and washed with carbon disnlphide, so as to remove 

 all traces of unaltered oil, etc., which is received in a tared flask; about 200cc will 

 suffice in any case. It is best to break up the mass after a partial exhaustion, espe- 

 cially when the product is hard and tough or soft and adhesive. 



Oils, fats, resins, rosin oils, petroleum, etc., not acted on by sulphur chloride so as to 

 yield solid products, may be separated. The melting point of a fat before and after 

 separation of the oil is an interesting and useful matter. The viscosity of a mixture 

 containing an ingredient acted on by sulphur chloride is of importance in examining 

 lubricating compounds. Let us, however, remember that some resins yield insoluble 

 compounds with sulphur chloride. 



It is advisable to perform the experiments in duplicate, so as to obtain a check on 

 the result; the difference should not exceed what we allow on an ordinary commercial 

 analysis. 



The washing with disulphide is carried under pressure ; a foot blower is convenient, 

 but by closing the top of the filter tube, the clasping it with the warm hand will be 

 sufficient. The exhaust will in some cases give a further yield of solid products; 

 in these cases, if a larger quantity of chloride be used iu the first place, a harder prod- 

 uct will be obtained. This ia not to be recommended, unless for special purposes, 

 because uniformity is aimed at in the result, and it is not desirable to alter the oils 

 too much. 



The exhaust is weighed after removal of disulphide, and when the weighings are 

 constant this is deducted from the contents of the dish, by which we obtain the 

 weight of insoluble solid products. This procedure is more simple and reliable than 

 weighing the insoluble solid product. The smell and color of the exhaust will in 

 many cases reveal what the oil itself is, in spite of blending, refining, etc. 



The color and tenacity of the solid, product is so very characteristic in most cases 

 that no difficulty will bo felt in deciding what the oil or mixture is ; thus arachis 

 oil in lard or olive oil can be instantly detected from cottonseed oil. Arachis oil ia 

 largely adulterated with cotton oil, and I have no doubt that in mauy cases where 

 cotton is supposed to bo present as an adulterant the intention of a manufacturer has 

 been to use arachis oil. I propose to examine this double adulteration shortly. 



Sulphur chloride is sometimes decomposed when added t<> an oil; the deposited 

 sulphur is removed from the exhaust by washing with ether saturated with sulphur. 

 The oily portion is taken up, leaving the sulphur; we then obtain the weight of the 

 exhaust minus the sulphur. If much sulphur is present the exhaust has a cloudy 

 white appearance. This indicates, generally, that the chloride is in excess. 



"Chern. News, March 23, 1888, p. 113. 



