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Iniall component fcalcs lie heaped one on another, (at leafl as far as 

 tlie limner was able to obferve them) and fo many years had elap- 

 Icd between the formation of the firft Icale, and all tlie others which 

 were added to it. 



This cutting or dicing off pieces from the fcales, does not fuccecd 

 equally well in all, for ibmetimes their thinnefs caufes it to fail, but 

 if the extremity of each fcale can but be perceived, tlie age of the 

 Filh may be gathered from it with little danger of millake. In order 

 to fhcw this irregular kind of fe6lion, I caufed a fniall piece of that 

 defcription to be drawn from the microfcope, and tliis is Ihewn in 

 fg. 5, I K L M ; here the additional fcales produced every year, 

 fometimes appear of a darker Ihade than thcv arc in reality, and 

 therefore the yearly increafe in fize feems reprefented at I O and 

 M O, but the addition of three years' growth appears at I O K. At 

 fig. 6, between P and O, is fliewn the natural fize of the flice or 

 piece of fcale reprefented when magnified, ^tfg- 4. 



Since we now find, that the fcales of Fifhes are every year aug- 

 mented in the way I have been defcribing, we may form a pretty 

 good judgment as to the time when tliis augmentation is made by- 

 analogy to what we obferve in the other productions of nature, and 

 thence we fliall conclude that the additional fcalcs are comi)lcatcd at 

 that feafon, when the further growth ceafes. For this is evident in 

 trees, at lead fuch as grow in theie regions. The like alfo is the 

 cafe in regard to cows, for between certain fpaces of time, when 

 their growth is intermitted or ceafes and when it again returns, it is 

 fhewn in the horns, whence we gather that as many knots or rings 

 as are found on the cow's horn, fo many years of age is the animal. 



And, though this may not appear exa6tly in the fame manner in 

 all creatures, yet we muft allow, that fuch a diflinguifliing circum- 

 Itance exifls, and this is proved in the falling ofl^'of tlie iiair from ani- 

 mals, and the fhedding of feathers by birds, at certain regular periods. 



