I 261 ] 



XLI. On a new Fossil Resin. By J. W. Mallet, Ph.D.* 



THIS mineral is from the coal measures in the neighbourhood 

 of Wigan ; of its exact localitj^, however, I am ignorant, 

 as well as of the nature of the matrix in which it was found, as 

 the specimen which came into my hands was quite detached. 



It occurs massive in small drops or tears of round and ovoid 

 forms, varying from the size of a pea to that of a hazel nut. 

 Sometimes two or three of these di'ops are stuck together. 

 Brittle ; breaking with a very distinct conchoidal fracture. 

 Colour — by reflected light black — by transmitted dark reddish- 

 brown. Streak, cinnamon-brown. Translucent only in veiy 

 thin splinters. Lustre, between vitreous and resinous, rather 

 brilliant. Spec. grav. = 1*136. Hardness = 3. Possesses a 

 slight resinous odour when pulverized. 



Heated on platina foil it swells up, takes fire like pitch, and 

 burns with a disagreeable empyreumatic smell and a smoky 

 flame, leaving a coal rather diflacult to biu'n, and finally a little 

 gray ash. ^Mien heated in a glass tube closed at one end it 

 jnelds a little water, swells up, melts, giving off a large quantity 

 of a yellowish-brown oily product of a nauseous empyreumatic 

 smell, and leaves a residue of carbon. It is insoluble in water, 

 alcohol, sether, caustic and carbonated alkalies, or dilute acids. 

 Even strong nitric acid acts on it but slowly. For analysis it 

 was finely pulverized, boiled in successive portions of water, 

 alcohol and aether (by which treatment traces of a svib stance 

 resembling an oil were removed), and then dried at about 250° F. 



9"52 grs. of the resin thus purified left on incineration "35 gr. 

 of ash ( = 3'68 per cent.), consisting principally of carbonate of 

 lime, with traces of silica, alumina, and peroxide of iron. Most 

 of the drops wei'e coated externally with a little peroxide of iron, 

 but this had been removed before proceeding to the chemical 

 examination. A portion of the mineral was tested for nitrogen, 

 but none was indicated. For the determination of the carbon 

 and hydrogen, chromate of lead was employed ; by combustion 

 with which 6'32 grs. gave 17'78 grs. of carbonic acid and 5*04 

 of water; and in a second experiment, 6"96 grs. gave 1968 car- 

 bonic acid and 5"68 water. 



From these numbers the per-centage composition of the resin 

 turns out to be — 



Carbon 7674 77-15 



Hydrogen .... 8-86 905 



Oxygen 10-72 1012 



Ash ^_3"^ 3-68 



100-00 10000 



* Commuuicati'd by the Author. 



