98 SHELLS USED FOR LIME. 



inhabitants of the maritime parts of Africa, of India, China,* 

 and of New Holland, are equally dependent on the same 

 source for their supply of this necessary article, hence the 

 consumption of shells over this the greater half of the globe 

 must be enormous, and must retard, if not entirely nullify, 

 their accumulation into banks and beaches. To restore the 

 molluscans to their pristine influence in the mutations of the 

 earth's surface, it would be necessary to render it first unfit 

 for the residence of man, or that he should grant them the 

 petition of the dead " leave me, leave me to repose ! " 



I here conclude what I had to tell you in relation to the 

 economy and uses of the mollusca. In my next, my en- 

 deavour shall be to give you a view of the system which 

 Cuvier has invented for their classification, when we shall 

 be prepared to enter on what relates to their structure and 

 physiology. 



of the bay of Londonderry, commonly called Loughfoyle, lie several emi- 

 nences, that hardly appear at low-water ; these consist of shells of sea-fish 

 of all sorts, more particularly of periwinkles, cockles, limpets, &c. The 

 countrymen come with boats at low-water, and carry loads of these shells 

 away; they leave them in heaps on the shore, and there let them lie till 

 they drain and dry, to render them lighter for carriage ; they then carry 

 them by boats as far as the river will permit, and then in sacks on horses, 

 perhaps six or seven miles into the country. They allow sometimes forty, 

 but mostly eighty barrels to an acre. These shells agree with boggy, heathy, 

 clayey, wet, or stiff land, but not with sandy." " The manure continues so 

 long, that none can determine the time of its duration. The reason of which 

 seems to be, that these shells dissolve every year a little, till they be all 

 spent, which requires a considerable time ; whereas, lime, &c. operates all in 

 a manner at once ; but it is to be observed, that in six or seven years the 

 ground grows so mellow, that the corn on it grows rank and runs out in 

 straw to such a length that it cannot support itself, and then the land must 

 be suffered to lie a year or two, that the fermentation may abate a little and 

 the clods harden, and then it will bear as long again, and continue to do so, 

 with the like intermissions for twenty or thirty years. In the years in which 

 the land is not ploughed, it bears a fine grass, mixed with daisies in abun- 

 dance, and it is pleasant to see a steep high mountain, that a few years 

 before was all black with heath, on a sudden look white with daisies and 

 flowers. It fines the grass, but makes it short, though thick." " Some 

 thousands of acres have been improved by the shells, and that which formerly 

 was not worth a groat per acre, is now worth four shillings ; they have in 

 many places thus improved the very mountains, that before were mere turf 

 bogs." Phil. Trans, abridg. v. 404 5. See also Phil. Trans, abridg. ix. 82. 



On the use of shells in agriculture in America, see Gould's Report Invert. 

 Massachus. 361. 



* The Chinese " not only burn lime from the oyster-shells, but likewise 

 make use of the largest in their buildings, instead of bricks." OSBECK'S 

 Voy. to China, ii. 317. See also STAUNTON'S Embassy, iii. 432. 



