MABERY AND HUDSON. — AMERICAN PETROLEUM. 103 



portions, —20° to —10°, the distillation proceeded from the heat of the 

 surrounding sitmosphere, and it was regulated by cooling the still. The 

 results obtained in the study of these distillates were so unexpected, the 

 entire process of distillation was repeated several times during the colder 

 months of the present year until in all 250 litres of 88° and 92° 

 •rasoline have been distilled, the portions below 12°, twenty times. The 

 interesting results in the distillations of the present year, especially in 

 excluding a butane at 8°-9°, are due to the patience and care of Mr. 

 Whitfield. 



In studving the derivatives of these hydrocarbons, the chlorine substi- 

 tution products were first formed by bringing toi^ether chlorine and the 

 vapor of the hydrocarbon. The method we employed differed somewhat 

 in details from the method of Schorlemmer.* In the reaction between 

 chlorine and the hydrocarbon, the intensity of light must be carefully 

 rculated. In direct suuli£;ht so much heat is developed that a flame 

 appears wiih the separation of carbon. In a cloudy day the action pro- 

 ceeds slowly, and with less light it is suspended. We obtained the most 

 satisfactory results both as regards the progress of the reaction and the 

 yield of the monochlor derivative in clear sunshine with a sheet of news- 

 paper interposed. In all our distillates the action of chlorine has pro- 

 ceeded with great readiness in the cold. The distillates collected below 

 0° were well cooled by means of a freezing mixture. The condensation 

 of the chlorinated product was more complete in a capacious bottle, — a 

 two-litre bottle for 100-200 c.c. of the oil, with the delivery tube extend- 

 ing half way from the top of the bottle to the surface of the liquid. The 

 heavier chlorine comes into intimate contact with the vapor of the oil, 

 and the product condenses for the most part on the side of the bottle. 

 Some of it unavoidably escapes with the hydrochloric acid, and it may be 

 condensed in part by placing in front another bottle well cooled, or still 

 better by passing the escaping gas through water. We have not found it 

 essential to separate by distillation the chlorinated product from the hydro- 

 carbon until the action was finished. If it be stopped with a small amount 

 of the hydrocarbon unchanged, which may easily be determined by ex- 

 perience, the product is nearly all the monochlor-compound. The use of 

 iodine suggested by Schorlemmer has not seemed essential, at least in the 

 formation of the l)utane derivatives, since, without it, there is no difficulty 

 in obtaining 80 per cent of the monochlor-compound, the remainder con- 

 sisting for the most part of unchanged hydrocarbon, nor in our experience 



* Philosophical Transactions, CLXII. Ill (1872). 



