KIMEBIDGE CLAY 23 



The shale has long been used for fuel by the people of the district -where it occurs, 

 and the ashes left after combustion have long been known to the farmers on the coast 

 to exercise a beneficial influence upon their crops, especially turnips ; but the unplea- 

 sant smell given out by it when burning has prevented it from being used, except by 

 the poorer inhabitants. 



The composition of this gas, freed from carbonic acid and sulphuretted hydrogen 

 by passing through an ordinary lime purifier, was as follows : 



Olefiant gas and congeners 10-0 



Light carburetted hydrogen and hydrogen . . . 79-0 

 Carbonic oxide H-Q 



100-0 

 The composition of the coke produced was : 



Carbon 73'4 .... 72*8 



Ash ..... 34-3 . . . . 30-3 



107*7 103-1 



The excess above 100 arises from the presence of sulphides in the coal, which 

 during the process of incineration absorb oxygen, and are converted into sulphates. 



A ton of shale furnished 11,300 cubic feet of this purified gas, the- illuminating 

 power of which, used in the argand burner, consuming 5 cubic feet per hour, equalled 

 that of 20 sperm candles, while the percentage of coke remaining was 36'5. 



The liquid and solid products obtained by the distillation of the shale at a low tem- 

 perature, are an offensively smelling, dark brown oil, suspended in an aqueous liquid, 

 charged with sulphuretted hydrogen, carbonic acid, and ammonia. 



This oil, purified and distilled with water, furnished an oily liquid heavier than 

 water ; a tar-like residue being left in the retort. 



The oily liquid which, when purified, gives out the odour of the finest varieties of 

 coal-gas naphtha, is a mixture of several chemical substances. 



"When treated with concentrated nitric acid, this oily liquid is divided into two 

 portions, one of which is dissolved by the acid, while the other insoluble portion 

 floats on the surface of the solution in the form of a light colourless oily liquid, 

 resembling in its general character the hydrocarbons of Boghead coal-tar, and of 

 petroleum. The nitric solution which forms the larger proportion of the oily liquid, 

 when mixed with water, furnishes a dense, heavy, yellowish oil, with the odour of 

 nitro-benzol. 



Hence it appears that the oily liquid obtained by the distillation of the shale con- 

 sists chiefly of benzol and its homologues, mixed with small quantities of petroleum 

 hydrocarbons. When sufficiently purified it is applicable for all the purposes for 

 which benzol is employed, for dissolving India-rubber and gutta-percha, for re- 

 moving stains from fabrics, for preparing Garnishes, for making artificial oil of 

 almonds, &c. 



On subjecting to distillation without water, and at a rather high temperature, 

 the oily tar-like residue remaining in the retort after the crude volatile oil is ob- 

 tained by heat from the shale, had been distilled with water, other volatile products 

 are obtained. 



The first portion of the oil obtained during the distillation is of an amber colour 

 when first distilled, and much less limpid than the oil produced by distillation with 

 water. It also possesses an offensive sulphurous smell, which, however, is lost on 

 exposure to the air, while the oil assumes a much darker colour. This oil is acted 

 upon by sulphuric, nitric, and hydrochloric acids, by which, especially by the first, a 

 portion of it is resinified. 



The remaining portion of the oil, when washed with water and afterwards dis- 

 tilled with steam, furnishes a perfectly colourless oil with the properties of paraffine. 

 This last oil, which forms but a small portion of the original oil, behaves in all 

 respects like the paraffine oil obtained from Boghead cannel coal, and is applicable 

 to the lubrication of machinery, and all the other purposes to which that liquid is 

 applied. 



The black, pitch-like, coky residue left in the retort resembles in general character 

 the coke produced from coal in tho manufacture of gas. 



The ash of the incinerated coke contains nearly the same proportions of silica, 

 alumina, and iron, as Portland cement. The following is an analysis of the ash left 

 by the shale, which contains the larger amount of mineral matter : 



