382 Scientific Intelligence. [Nov. 



ment, and found that though two of our party were unable to 

 swim, they were buoyed up in a most extraordinary manner. 

 The sensation perceived immediately upon dipping was, that we 

 had lost our sight ; and any part of the body that happened to 

 be excoriated smarted excessively. The taste of the water was 

 bitter and intolerably saline. From this experiment some of us 

 suffered a good deal of inconvenience, an oilv incrustation being- 

 left upon the body, which no attempt at washing could remove 

 for some time ; and several of the party continued to lose por- 

 tions of skin for many successive days." — (Ibid. p. 192.) 



I can understand the meaning of every part of the preceding 

 description, except the alleged loss of sight. It deserves notice 

 that the specimens of salt collected from the southern extremity 

 of the Dead Sea did not deliquesce. This was doubtless owing 

 to the dryness of the climate • not to the purity of the salt. 



V. Climate of Moscow. 



The severest frost of the winter 1817 — 1818 was equal to 



— 28° Reaumur (—31° Fahrenheit). In Petersburgh they had 



— 30° (— 35^° Fahrenheit). But this winter was reckoned a 

 mild one, for the quantity of snow was unusually great ; the best 

 proof of its mildness ; for in very severe weather, there falls but 

 little snow. — (Ibid. p. 271.) 



VI. Population of Moscow. 



When the French quitted Moscow, there were only 16,000 

 inhabitants; but in the winter of 1817 — 1818, the population 

 amounted to 312,000, including 21,000 military.— (Ibid.) 



^ 11. Xcw Acetate of Lead. 



Chailes Macintosh, Esq. who has long been a manufacturer 

 of sugar of lead in Glasgow, accidentally obtained, some months 

 ago, a salt in large flat rhomboidal crystals, which obviously 

 differed in their shape, from the crystals of common sugar of 

 lead. Happening to visit the manufactory while these crystals 

 were still in Mr. Macintosh's possession, I carried away a suffi- 

 cient quantity of them to enable me to determine their properties 

 and composition. 



The crystals were white and translucent, and consisted of flat 

 rhomboidal prisms, with angles of 106° and 74°. Each prism 

 was terminated by a dihedral summit, formed by two faces pro- 

 ceeding from the narrow faces of the prism, and meeting at an 

 angle of 130°. These crystals were not altered by exposure to 

 the air. 



The taste of the salt was sweet and astringent, similar to the 

 taste of common sugar of lead. Its specific gravity was 2*575. 

 AX the temperature of 60°, 1 00 parts of water dissolved 34'8 

 parts of the salt. It was soluble also in alcohol, as is the case 

 with common suaar of lead. 



