288 ECONOMIC GEOLOGY. 



exceeding that of ordinary coals. The latter are merely earthy beds 

 impregnated with hitumen, not applicable as fuel, from the circum- 

 stance that the combustible portion melts, and flows through the bars 

 of the furnace, but generating an amount of gas ,in some instances, 

 double the volume of that obtained from the regular coals. The 

 Trinidad pitch formation also consists of bituminous elements inti- 

 mately mixed with a variable per centage of earthy matter. It is 

 natural to conclude that well directed experiments might produce 

 results ajipoximating to those afforded in the instances referred to. 



ATMOSPHERIC INFLUENCES. 



Atmospheric variations in all climates have a material influence on 

 the harvests of a country, and nfthing less will suffice to the full 

 understanding of the peculiarities of climate than the comparison ot 

 observations on atmospheric phenomena made throughout entire 

 years. On this account, a record of meteorological data has been 

 executed by the geological department, and on a scale as complete as 

 circumstances would allow. 



ANALYSIS OF SOILS. 



The elementary constitutions of the soils, as well as their exhaus- 

 tion by cultivation, has also received attention, and a series of chemical 

 analysis of typical soils, and subsoils, is in progress, but the great 

 expenditure of time involved in researches of this nature has rendered 

 it difflcult to combine them with the duties more especially apper- 

 taining to the department. 



PICTORIAL REPRESENTATIONS. 



No written descriptions of a country can convey so faithful an idea 

 of its structure or appearance as when accompanied by pictorial 

 representations. The district geologically examined is amply illus- 

 trated by drawings' of interesting scenery and peculiar geological 

 features, 



SPECIMENS. 



The specimens collected during the examination, and illustrative of 

 the geology of the island, are arranged at the office of the survey, for 

 the inspection of such as experience an interest in the progress of the 

 inquiry. 



