54 ME M O I R S of tk 
above one in a hundred are tolerably clear, yet a vaft nunnbcr of 
fair merchantable pearls are every year Ibid by thole people 5 and 
Sir Robert himfelf faw a pearl that weighed 35 carats, and was 
valued at 40 /. the young mulcles are never obferved to have any 
pearl in them 5 the fhell is faftened with two tendons, one at each 
end, whereas the oyfler and fcallop have only one in the middle 5 
they lie in part open, putting forth their white fins, like a 
tongue, by which the eye is directed to them, being otherwile as 
black as the flones in the river 5 the backs of the ihells both in 
young and old, juft about the hinges, on which the valves 
open, are all broken and bruiled, and fhew the feveral crufts and 
fcales that make up the fhell, which is probably cauled by the 
rolling of large (tones over them in great floods 5 the infides of the 
fhell are of an oriental and pearl-colour and fubflance, like a flat 
pearl, efpecially when firft opened 5 and there is oblerved in fome 
ihells under the firfl coat a liquor very orient and clear, that 
moves upon prefTure by the finger, but fuch a mulcle never has a 
pearl; and probably this liquor is the true mother of pearl: The 
pearl lies in the fmaller extremity, at the end of the gut, and 
out of the body of the fifh, between the two films or fkins that 
line the Ihell 5 it is probable that the pearl anfwereth to the Hone 
in other animals, and it is certain that in the lame manner it en- 
creafes by feveral crufts growing over each other, which appears 
by pinching the pearl in a vice 5 for the upper coat will crack and 
fly away, and this ftone is caft out and voided by the mufcle; for 
many ihells that have had pearls in them, are afterwards found 
to have none 5 the fhells that have the beft pearls are wrinkled, 
twifted or bunched, and not fmooth and equal as thofe that have 
none 5 it is thought, that thefe pearls, if once dark, will never 
become clear upon any alteration in the health or age of the 
mulcle 5 and that if the leed be black, all the coats fuperinduced 
will be ilill clouded. 
^n Jlccomn of digging and preparing the Lapis Calaminaris ♦ 
by Mr, Giles Pooley. Phil. Tranl." N° 198. p. 611. 
TH E Lapis CalaminariSy or Calamine, is dug and prepared 
near Wrington in SomerfetjJnre j the groovers have no 
certain rule to direct them in finding it out, either from the fur- 
face of the earth, or the nature ot the ground 3 it being fom,e- 
;imcs found in meadows, ibmetimcs in arable, and fometiraes 
again in pafture grounds, and very commonly in barren and rocky 
ground 5 nor is it difcoverable from the colour or tafte of the wa- 
ter, as being much of the fame colour, tafte, clearnels and whol- 
fomnels 
