One T/touscuid Expeiimenls, 6,c. 363 



called alcalizing these solvents. Now put the turpentine, or 

 spirits, into a vessel with two ounces of clean dry copal, finely 

 pounded and sifted ; place the vessel in warm water; the copal 

 will soon be dissolved." " Observations." " If the spirits of tur- 

 pentine be alcalized when the copal is dissolving, a little spirits 

 of wine should be added; and if the spirits of wine be alcalized 

 when the copal is dissolving, a iittle spirits of turpentine should 

 be added ; the sediment of the varnish will dry on the silk in a 

 few hours; the thicker the varnish, the sooner it dries." On this 

 occasion, as with most other of his practical recipes, Mr. Mac- 

 kenzie has been humbugged by the workmen to whom he has 

 addressed himself. The above process is good for nothing. An 

 ounce of dry carbonate of potash will not dephlegmate a pint of 

 the alcohol of the shops, and the copal instead of being soon 

 dissolved might remain there till dooms-day. 



We presume, we have now satisfied every reader of ordinary 

 intelligence, that this costly octavo is so devoid of scientific 

 views, and so replete with practical errors, as to render its pe- 

 rusal useless to the student, illusory to the political economist, 

 and deceitful to the artisan. Here and there, we meet with ex- 

 tracts from respectable authors, inserted often without acknow- 

 ledgment, and always without direct reference to the source 

 whence they are immediately derived. But, in general, the book 

 is a cento of obsolete and exploded operations. We close these 

 remarks, flowing solely and sincerely from a wish to protect our 

 countrymen from deception and loss, with the following sentence, 

 very slightly altered from the author's note to page 274. " It is 

 hoped that none of the experiments will be repeated through 

 wantonness." In this case, we are sure they will not be tried at 

 all ; for neither profit nor instruction can result from their repe- 

 tition, as described by Mr. Colin Mackenzie. 



iii. Philosophical Transactions of the Royal Society, of London, 

 for thcxjcar 1821. Part II. 



In resuming our account of the Philosophical Transactions for 

 the year 1821, we shall lay before our readers a brief abstract 

 of the principal facts contained in the several papers published 

 by the Royal Society, examining them in the order in which they 

 stand in the volume. 



\. An account of Experiments to determine the acceleration of the 

 Pendxdum in different Latitudes. Dij Captain Edward Sa- 

 bine, of the Royal Regiment of Artillery, F. U.S. & F.L.S. 



To the merit of Captain Sabine, as an accurate and ariiti> 

 observer, wo have more than once had occasion to advert ; lu: 

 2 B 2 



