AN ADVENTURE AT SEA. 257 



composition. Crystalline cleavage was illustrated by carbonate 

 of lime, which divided into rhomboids, and this division might be 

 continued, at precisely the same angles, and at these only, down 

 to the most minute particle, and this was shewn to be an universal 

 property, extending through the whole range of mineralogy ; and 

 in fact through crystallography of all kinds ; and that by the 

 angles thus developed, substances may, with certainty, be distin- 

 guished one from another. 



But it appeared that carbonate of magnesia gave the same 

 angles as carbonate of lime ; and that the very same result also 

 from the cleavage of carbonate of iron, and of carbonate of lead. 

 Hence that these substances might not only be confounded together 

 judging from their angles of cleavage; but that they do actually 

 crystallize together promiscuously : and the same property was 

 shown to hold in a great number of other instances. 



Some experiments made by Mr. Hearder, on combustion in 

 vacuo, previously before the Society, were also alluded to, to shew, 

 that in Chemistry, as well as in other branches of knowledge, the 

 Plymouth Institution was endeavouring to contribute its mite, 

 towards the general advancement of Science : and the reporter 

 expressed strong hopes that the coming year would do more for 

 its reputation than any preceding one. 



AN ADVENTURE AT SEA. 



The mate had been looking out with a spyglass, and observed a 

 sail to windward. 



" Jump aloft, one of you who has good eyes, and tell me what 

 you make out of that craft with the suspicious rake in her masts, 

 on our weather bow ! *' 



"Ay, ay, sir! '* they again sung out, in full chorus; and away 

 several scampered up the shrouds, pell-mell. Among the rest 

 was perceived the slight figure of the lad, who ascended with 

 remarkable agility, and left the others far behind. The mate 

 could scarcely credit what he saw, and gazed aloft in amazement. 



" Maintopgallant, there ! " hailed the mate. 



"• Ay, ay, sir!" replied Isaac, in as gruff a voice as he could 

 muster for the occasion. 



" What sort of craft is that to windward, — and how is she 

 standing ? " 



VOL. V. — 1835. II 



