362 PHILOSOPHICAL TRANSACTIONS. [aNNO 1773. 



paration. To prove this assertion, it may not be improper to recite what Pomet 

 says on the subject, as he appears to be the principal author whom the rest have 

 copied. After describing the fish, and referring to a cut engraven from an ori- 

 ginal in his custody, he says : '' As to the manner of making the isinglass, the 

 sinewy parts of the fish are boiled in water, till all of them be dissolved that will 

 dissolve; then the gluey liquor is strained, and set to cool. Being cold, the fat 

 is carefully taken off, and the liquor itself boiled to a just consistency, then cut 

 to pieces, and made into a twist, bent in form of a crescent, as commonly sold, 

 then hung on a string, and carefully dried." From this account, it might be 

 rationally concluded that every species of fish which contained gelatinous prin- 

 ciples would yield isinglass: and this seems to have given rise to the hasty con- 

 clusions of those who strenuously vouch for the extraction of isinglass from 

 sturgeon; but as that fish is easily procurable, the negligence of ascertaining 

 the fact by experiment seems inexcuseable. Every traveller, as well as author, 

 who mentions isinglass, observes that it is made from certain fish found in the 

 Danube and rivers of Muscovy. Willughby and others inform us, that it is 

 made of the sound of the beluga; Caspar Newman, that it is made of the huso 

 germanorum and other fish, which he has seen frequently sold in the public 

 markets of Vienna. These circumstances make it appear the more extraordinary, 

 that a perfect account of the manufacture of such an essential article of com- 

 merce should remain so long unrevealed. 



In Mr. J.'s first attempts to discover the constituent parts and manufacture of 



• Mr. Jackson died at Tottenham, June 29, 1 80 1 , at 84 years of age, where it is said he kept by 

 him for some time before his death, a patent coffin to be interred in, and used at times to lie down in 

 it, to show his acquaintances how it fitted him. Mr. J. kept a chemist's shop about Tower hill, 

 London, where it seems speculating on schemes how at once to make a great fortune, he fell on that 

 of brewing porter by certain drugs substituted as materials instead of malt and hops. With these he 

 set up as a general instructor of the brewers, to initiate them into these new mysteries, for saving malt 

 and hops, by giving private lessons in the art, at an enormous premivim. This art it seems they have, 

 in most instances, practised ever since in so extensive a manner, as to have produced a general com- 

 plaint, that the ancient national malt liquor is miserably degenerated, with universal execrations on 

 the memory of tlie man who could be so wicked as to introduce a practice, in consequence of which 

 the natural beverage of the country has been ruined for ever. Among other pupils of Mr. J. was the 

 late Mr. Thrale, the great brewer in the Borough, fi-om whom alone it seems this charlatan extracted 

 an ample fortune, as mentioned by Mr. T.'s widow, now Mrs. Piozzi, in her Anecdotes of the Life of 

 Dr. Johnson, 



After having by such means, in a short time, amassed an immense fortune, he was mean enough" 

 to retire to Woolwich, where he built a house, having one very large room, on purpose to practise as 

 an ignorant trading justice, extorting the shillings for oaths, and the paltry fines for the harmless of- 

 fences of the miserable poor around the parish. After thus continuing for a number of years the 

 meanest and dirtiest practices of the worst of his profession, till his abuses of office had rendered the 

 place too hot for his longer residence, he disposed of his property at Woolwich, and removed to carry 

 on his operations at Tottenham, where he died, as above mentioned. 



