140 ON THE METHOD OF ZADIG. [LECT. 



given to certain elongated stony bodies, ending at 

 one extremity in a conical point, and truncated at the 

 other, which were commonly reputed to be thunder- 

 bolts, and as such to have descended from the sky. 

 They are common enough in some parts of England ; 

 and, in the condition in which they are ordinarily 

 found, it might be difficult to give satisfactory reasons 

 for denying them to be merely mineral bodies. 



They appear, in fact, to consist of nothing but 

 concentric layers of carbonate of lime, disposed in 

 subcrystalline fibres, or prisms, perpendicular to the 

 layers. Among a great number of specimens of these 

 Belemnites, however, it was soon observed that some 

 showed a conical cavity at the blunt end ; and, in still 

 better preserved specimens, this cavity appeared to 

 be divided into chambers by delicate saucer-shaped 

 partitions, situated at regular intervals one above the 

 other. Now there is no mineral body which presents 

 any structure comparable to this, and the conclusion 

 suggested itself that the Belemnites must be the effects 

 of causes other than those which are at work in 

 inorganic nature. On close examination, the saucer- 

 shaped partitions were proved to be all perforated at 

 one point, and the perforations being situated exactly 

 in the same line, the chambers were seen to be 

 traversed by a canal, or siphuncle, which thus con- 

 nected the smallest or apical chamber with the largest. 

 There is nothing like this in the vegetable world ; but 

 an exactly corresponding structure is met with in the 

 shells of two kinds of existing animals, the pearly 

 Nautilus and the Spirula, and only in them. These 



