518 HISTORY OF 



skin, the entrails, the fins, and the tail of this fish, and cut them 

 into small pieces ; these are left to macerate in a sufficient quan- 

 tity of warm water, and they are all boiled shortly after with a 

 slow tire, until they are dissolved and reduced to a jelly ; this 

 ielly is spread upon instruments made for the purpose, so, tha' 

 drying, it assumes the form of parchment, and, when quite dry 

 it is then rolled into the form which we see in the shops.* 



This valuable commodity is principally furnished from Russia 

 where they prepare great quantities surprisingly cheap. Mi 

 Jackson, an ingenious countryman of our own, found out an ob- 

 vious method of making a glue at home that answered all the 

 purposes of isinglass ; but what with the trouble of making it, 

 and perhaps the arts put in practice to undersell him, he was, as 

 I am told, obliged to discontinue the improvement of his dis- 

 covery. Indeed, it is a vain attempt to manufacture among our- 

 selves those things which may be more naturally and cheaply 

 supplied elsewhere. We have many trades that are unnaturally, 

 if I may so express it, employed among us ; who furnish more 

 laboriously those necessaries with which other countries could 

 easily and cheaply supply us. It would be wiser to take what 

 they can thus produce ; and to turn our artizans to the increase 

 and manufacture of such productions as thrive more readily 

 among us. Were, for instance, the number of hands that we 

 have now employed in the manufacture of silk, turned to the in- 

 crease of agriculture, it is probable that the increased quantity 

 of corn thus produced, would be more than an equivalent for the 

 diminution of national wealth in purchasing wrought silk from 

 other countries. 



CHAP. VI. 



or ANOMALOUS CARTILAGINOUS FISHES. 



Of all others, the Cartilaginous class seems to abound with 

 the greatest variety of ill-formed ajiimals; and, if philosophy 



* Isingflass is prepai'od from various othor fishes, but principally from tlip 

 WliitP Holphin, or Belluga of North Araorica. This well-knowu substauc* 

 is made from the sound, or ;ur-b)addei'. 



