44 Observations upoii the 



Tiiese limits, which the resources of man cannot pass, 

 should render us very circumspect in the results we at- 

 tribute to them, since none of the substances in nature, which 

 man destroys or alters, can again appear, except by pursuing 

 the laws and the course established by the Creator from the 

 origin of things. 



M. Fleuriau de Bellevue mentions a singular production 

 of a lime iurnace, which lie quotes as an example in favour 

 of his system : " This production," he says, " resembles in 

 its interior certain horny rocks of the Alps, and some com- 

 pact and homogeneous lava. Its exterior is full of bubbles 

 like those of lava, its surface is covered with a yellow ena- 

 mel, audits cavities are overspread with small crystals:" 

 and he adds In a note, " Let it not be supposed that these 

 kinds of stones have fallen accidentally into these furnaces; 

 that is impossible." 



I shall not make any direct objection on this head; I must 

 be first acquainted with the production alluded to, and parti- 

 cularly with the neighbourhood of the lime kiln in question. 

 But I shall offer one general observation, which may throw 

 some light upon its origin. Examples are frequent of there 

 being introduced among the broken calcareous stones, frag- 

 ments of other stones, to which the workmen pay no atten- 

 tion, and which are only perceived when the lime is extracted : 

 there is then found, instead of a piece of linie, a stone covered 

 on its surface w ith a vitreous varnish, which on beins; broken 

 shows granite, serpentine, or any other vitrescible rock : 

 these examples are frequent in the lime kilns in our neigh- 

 bourhood. In order to be convinced that no such fragments 

 can be introduced, it must first' be proved that there are no 

 calcareous rocks in the country exempt from quartzose or si- 

 liceous nuclei, and that there are no other kinds of rocks, 

 belonging to the soil, or adventitious. It is also very proba- 

 ble, and I am persuaded of it from a great number of exam- 

 ples, that the production of the lime kiln mentioned is owing 

 to some other kind of stone than the species intended to be 

 calcined in it. 



" The naturalists," M. Fleuriau de Bellevue proceeds, 

 *'who still think that the rocks upon which the volcanic fires 



have 



