428 INDEX. 



alkaline earths, 133-137; on the atomic weights of the vege- 

 table acids, ibid., 130 ; remarks on the style of his writing, 139- 

 141 



Thorina, compound nature of, demonstrated, 391 



Titanic acid, separation of, from the oxide of iron, 176, 177 



Titanium, (metallic) found in iron furnaces, 176 



Torricellian tube, on the alteration in the bulk of successive por- 

 tions of air introduced into, 37S, 379 



Transits of Venus, method of computing the sun's horizontal pa- 

 rallax from, observations of the, 94-98 



Tyrant Shrikes of America, observations on, 267-2S5 



Tungsten, notice of, experiments on its combinations, 177-180 



Water, globules of, found in amethyst, 187 ; action of, upon 

 glass, 259-264; use of, in formation of lead plaster, 400, 401 



Weights and measures, account of the construction and adjustment 

 of the new standard of, 299-303 



White, (John, Esq.) experiments and observations on calcareous 

 cements, 50-57 



Wohler, (M.) experiments of on tungsten, 177-180 



Urines, peculiar blue matter obtained from certain, 409-411 



Variolus eruption, employment of caustic for the destruction of, 200 



Vauquelin, (M.) examination of the solanum pseudo-quinia, 181,182 



Vegetable kingdom, action of poisons on the, 191-190 



Volcanoes, considerations on, 356-374 



Voltaic piles, (dry) notice of, 169, 170 



Yew tree at Peronne, notice of the age of, 412 



Zamboni, (M.) on a dry voltaic pile, 169, 170 



END OF THE TWENTIETH VOLUME. 



Pa?e 58, Ui 



263, l^^.tfAr pp»l.]^Ja|ly v st : ftlo/. read pearly scaler, 

 ine read sensibly so. 



Printed by W. Ci.ovvfs, NoitbumberlaiKl-C* 



