400 NAPHTHA, NATIVE 



legislation is based on the fact that light vapours arise many inches from the surface 

 of the oil, and can be ignited there long before the body of the oil takes fire. In the 

 open test which was first prescribed by Act of Parliament, the vessel holding the oil 

 was inclosed in a water-bath heated by a spirit lamp, a thermometer again inserted, 

 the whole protected by a screen extending half round the surface of the vessel, and a 

 match, in, say the form of a piece of string, applied a full inch at least above the sur- 

 face of the oil. In the close test the surface of the oil-holding vessel is covered ; 

 openings only being left for the firing-string and the thermonreter. There is a dif- 

 ference of 15 to 25 in the firing- point of the two tests ; the tests reduce the degrees 

 in the inverse order to that in which they have been given. An American cargo with a 

 firing -test certified at port of transit, will have it diminished about 10 by the open 

 test, and 20 by the close test. The law now stands for Britain prohibiting the sale 

 of petroleum under 100. It varies in different countries. At Antwerp, which regu 

 lates the petroleum importation of Germany, there is no prohibitory enactment. The 

 State of Maine, U. S., specifies 115 igniting test, whilst Massachusetts and Vermont 

 agree on 110 Fahr. (See ' Report of Select Committee of the House of Lords on the 

 Petroleum Bill, 18?2.') 



Petroleum and paraffin spirits or naphtha have also acquired the synonym of 

 ' turpentine-substitute,' because of their application in varnishes and other house 

 paints ; but, as the name implies, cheapness mainly regulates this use. 



Hirzel (Spec. A. D. 1863, No. 2987) proposes to extract essences and perfumes, by 

 petroleum spirit, as a substitute for bisulphide of carbon. Others have patented this 

 substance as an extractor of vegetable and animal oils. G. Ville, the French agri- 

 cultural chemist, shows that were this method applied to the culture of the ordinary 

 oleaginous plants much good would result. If 35 hect. of the colza were treated 

 ordinarily by hydraulic press, 808 kil. of oil would be given ; but by the aid of petro- 

 leum spirits the produce is increased to 1,039 kil. (See Les Engrais Chimigucs, par 

 M. G. Ville, torn. ii. p. 176, &c. Paris, 1872). 



Ville is inclined to think that from 6 to 8 per cent, of oil is left in seeds after the 

 action of the hydraulic press. Of course where oleaginous plants are mainly grown 

 for their oil and fibre, as in the Western States of America, or where the cake is 

 returned as a manure into the soil, as recommended by G. Ville, this process is com- 

 mercially' available. 



Sponge lamps have been suggested to use mineral spirits either as portable gas for 

 illuminants or a quick and ready heating-power. The chandlers last winter exhibited 

 at least two ingenious French contrivances for this purpose. With proper precautions, 

 no danger can supervene. Any other hydrocarbon incautiously managed will cause 

 peril. Turpentine emits a volatile vapour a little above 110 F. ; and a can of it kept 

 in a storehouse a little above the boiler is said to have caused an explosion resulting 

 in the famous burning of the steamer ' Amazon." Other like calamities have been 

 traced to this source. Such volatile oils expand at the rate of 1 in 30 in -a tempe- 

 rature of 60 F., that is to say, between 40 F. and blood-heat ; other oils of the 

 series expand at correspondingly higher temperatures. The oil which gave its sad 

 pre-eminence to the Abergele accident was a Welsh-made oil of 130 spec, grav., and a 

 high firing-point. When such vapours mix with atmospheric air in the proportion of 

 1 in 7 or thereabouts, an explosion occurs on the proximity of a light. 



On first igniting a paraffin lamp, the heat from the burning wick causes the lighter 

 oils to ascend in vapour. Should the whole contents of the reservoir be too suddenly 

 raised into vapour, manifestly 'there's death in the pot." A dangerous oil will assume 

 this state at 80 or 90 F., but only a very small portion of a safe oil will vaporise at 

 these temperatures. Dr. Lyon Playfair gave the following evidence before a recent 

 Parliamentary Committee : ' I would burn no oil in my own house, nor would I advise 

 a friend of mine to burn any in his house, under 120 F. as the very minimum, but I 

 should prefer 130, that is to say, 120 for the vapour, and 130 for the permanent 

 ignition. Oil with a high firing-point gives out more light than the other kind. It 

 burns quite as long and gives out more illumination. A gallon of oil at 130 of 

 permanent ignition, produces 25 per cent, more light than a gallon at 100. The 

 light from the low-igniting oil is not more at the time it is burning, but those who 

 are accustomed to burn light petroleum, sometimes like it better than heavier and 

 safer oils, as they find that they can manage the wick more easily.' 



At an expense of about 2d. per gallon, petroleum can bo refined so as to be perfectly 

 safe. 



The following remarks on the formation of naphthaline from practical gas manu- 

 facturers are of considerable interest. Mr. Hyde, at a meeting of the Gas-light 

 Association of the United States held at Cleveland, after generally describing this 

 substance, proceeded to say : It had a peculiar faintly aromatic odour, not unlike 

 narcissus ; it was heavier than water, and was readily dissolved by naphtha. During 





