VOL. XV.] PHILOSOPHICAL TRANSACTIONS. 125 



Of the Scales of Eels. — Among the fishes which are generated in our rivers' 

 and waters I know but of two sorts that are said to have no scales', the one 

 sort is the eel and paelink, in some places not distinguished, but with us they 

 are distinguished, the paelink being flatter and pleasanter in taste, and therefore 

 sold dearer; the 2d sort is the eelpout; this last sort are short and thick, and 

 scarcely to be met with; which two sorts of fish the Jews will not eat, as for- 

 bidden by the law of Moses. 



I examined the skins of these fishes, after I had cleared them of their slime, 

 and found them covered with scales as much as other river fish, for the scales, 

 although very thin and small, lay orderly, and close fastened one over the other. 

 Besides, these fishes are also provided with fins, like other fish ; for they have 

 on each side of the head a perfect fin, the whole hinder part or tail is, both 

 above and under, furnished with a continued fin. 



The Chemical Touch-stone of M. John Kunhel, Gentleman of the Bed chamber 

 to the Elector of Brandenburg, De ^cido, et Urinoso Sale Calido et Frigido, 

 contra Doctor. Foightii Spirit. Fini vindicatum. Submitted to the Royal Society 

 of London, iSc. as to the High Judges of this Matter. Berlin, the 6th of 

 July, 1684.* N° l68, p. 896. 



This book sent to the Royal Society by favour of the Elector of Branden- 

 burg, is written in high Dutch. 



The author begins with an epistle dedicatory to the Royal Society, appealing 

 to them as to impartial judges. 



He then addresses to the reader an apology against some calumnies thrown 

 upon him. After this, follows a short epistle of M. Kunkel's antagonist. Dr. 

 Voight, to Dr. Martin Weisen; addressed to him as judge of the controversy. 

 M. Kunkel begins to lay down his opponent's propositions, which are three. 

 1 . That there is no acid which of itself gives either heat or flame ; for he says, 

 that there is no acid of either the vegetable, mineral, or animal kingdom, which 

 affords it. He instances in the acidum ventriculi et succi pancreatici; whereas 

 on the contrary, the gall, which contains no acid but affords oil, gives also 

 flame and heat. 2. He endeavours to prove spirit of wine to be an oil. 3. He 

 obviates some objections. 



M. Kunkel in answer says, that he never declared it as his opinion, that 

 any body should produce heat, without the accession of a frigidum, which in 



* The principal facts and arguments stated in this curious controversy it has been thought fit to pre- 

 serve, as tending to show the progress which chemistry had made at the period above-mentioned, 

 and what were the chemical theories which then prevailed. 



