388 Objeétions to the Mitchillian 
13. In the laft place, feveral confequences, of importance 
to chemiftry and the arts, arife from thefe principles, 
After this conclufion it will be afked, no doubt, how it 
happens that the fimple matter, pure carbon, the diamond, 
as fo rare while its compounds in different ftates are fo abun- 
dantly diffufed? To put an end to the aftonithment of thofe 
who might entertain any miftruft, I thall obferve, that alu- 
minous earth is alfo one of the moft common matters, and 
that adamantine fpar, as rare as the diamond, is however 
only alumine; that iron every where exifts, under all forms, 
except in the ftate of purity; the exiftence of native iron is ftill 
doubtful. The wonder exifts only in the oppofition of faéts 
to gur opinions, and will difappear in proportion as we dif. 
cover, and appropriate to ourfelves, the means employed by 
nature in producing the fame effects, 
Thofe who have never turned their attention to the hi 
fical fciences, to eftimate at leaft their influence on public 
- _ felicity, are difpofed to treat as vain curiofity labours which 
are not immediately directed towards a near objet of new 
enjoyment. What would have been their aftonifhment had 
they been told, that refearches on the nature of the diamond 
would one day produce truths which might give rife to 
happy changes in the practice of the moft familiar arts; in 
the preparation, and in the employment of the coarfeft com- 
buftibles! Such, however, are the confequences that may 
arife from the beft known properties of the effential principle 
carbon in its different ftates. 
XI. A Letter to the Editor, containing fome Objeétions to the 
Mitchiluian Theory of Peftilential Fluids. 
STR, 
OBSERVE, in the 15th Numher of your ufeful Maga+ 
zine, a communication from Dr. Mitchill, of New-York, 
fhewing the utility of conftructing the witht and paving 
the ftreets of cities, with calcareous in preference to JS liceous 
and argillaceous materials. This communication is con- 
tained in a letter from Mr, Da Cofta to the Dodtor, in which 
it 
