DEAR SIR, 



CONCEIVING that a portion of the opaline wood being mixed 

 with twice its weight of purified nitre, and exposed to heat, if carbon was 

 present in the stone, it would unite with the oxygen of the nitre, and produce 

 carbonic acid gas, I proceeded to the following experiment. 



Into a coated glass retort, with a conducting tube entering a bottle of lime- 

 water, 50 grains of fossil wood, and 100 of nitrate of pot-ash, were introduced ; 

 and it was then surrounded with heated charcoal. After the expansion of the 

 atmospheric air, an absorption took place, from the fusion of the nitre; this 

 was guarded against, by lifting the conducting tube from the water ; as soon 

 as gas was liberated, it was again immersed, and a copious precipitation, and 

 cloudiness of the lime-water, ensued. This continued for some minutes j it 

 was then succeeded by the liberation of oxygen gas, with nitrous gas, occa. 

 sioning no precipitation in fresh lime-water. In 36 minutes the retort was 

 perfectly white hot, and slight absorption began to take place : the retort was 

 then removed, and when cool was broken : the mass was found strongly agglu- 

 tinated, possessing a tinge of pink. 



I am, with sincere respect, yours, 



W. H. PEPYS, jun. 



The presence of carbon having been thus proved, my next eager 

 wish was to endeavour to discover the nature of this substance, 

 which thus contained carbon as a principle ; entertaining an ex- 

 pectation, that some evidence would appear, that it was vegetable 

 matter, which had undergone the biturhinizating process, or fer- 

 mentation : 1 therefore requested Mr. Pepys, without mentioning 

 my conjecture, to submit a portion of similar fossil wood, with that 

 which had been employed in the foregoing experiments, to simple 

 distillation, over a naked fire. This request was kindly complied 

 with, and the result appears in the following letter. 



SIR, 



AGREEABLE to promise, I have made the experiment you requested. 



250 grains of the opaline wood were pulverized, and placed in a coated 



glass retort ; to which a tubulated receiver, with a conducting pipe, leading 



into a bottle of lime-water, was luted. Gradual heat being given, rarefied 



the atmospheric air in the vessels, which passed through the lime-wafcer ; in 



