Scientific Intelligence, ^c, 229 



acid, pyroxylic spirit passes with the new compound. According to 

 Dr. Apjohn, who analyzed it, 4 grs. afforded of Carbon 2-967, 

 Hydrogen -343, Oxygen -790. Its composition agrees with C^o 

 H^ 02. 



2. Mr. Cross made some remarkable observations on Atmospheric 

 Electricity. He had constructed an isolated electrometer by passing 

 a wire on the extremity of a long pole 110 feet high for a mile into 

 the atmosphere. By means of this apparatus he had found that the 

 atmosphere is always positively electrified. The electricity after 

 sunrise is always at its maximum ; the quantity of electricity from 

 fogs is enormous. Every thunder-cloud, he found, consisted of 

 positive and negative electricity in the form of zones, consisting of 

 insulated particles of water. Mr. Cross had formed a young thunder- 

 cloud by breathing on a pane of glass, and electrifying the middle 

 by a spark from a Leyden phial, and thus formed zones. He has 

 never observed any effect upon the wire by meteoric lights, nor by 

 sheet lightning. He has constructed a battery in which no acid is 

 used ; the cells being insulated and the connecting medium being 

 water. By means of this battery he has crystallized many minerals, 

 as calcareous spar in 10 days, silica, &c. Between 7 and 10 A.M. 

 the battery is at its maximum, and at its minimum between the 

 same hours in the evening. Crystallization is more rapidly effected 

 in the dark than in the light. If the shutters of the rooms be 

 opened before 7 A.M. the maximum is lower. 



3. Dr. Trail on the Aurora borealis. 



II. — Pliarmacyy ^'c. 



1. Gamboge. — According to Dr. Graham the substance is the 

 product of the Garcinia or 3Iangostana 3Iorella. Dr. Christison 

 states, that the present gamboge of commerce does not come from 

 Ceylon but from China, as in the time of Bontius. He found 

 gamboofe in sticks from Siam, to consist of resin 72*2, arabin 23, 

 water 4-8. Gamboge in cakes from Siam, consisted of resin 6'48, 

 arabin 202, fecula 5*6, woody matter 5'3, water 4,1. Gamboge 

 from Ceylon, sent by Mr. Walker, contained, resin 70*2, arabin 19-6, 

 fibres of wood and bark 5*6, water 4*6. Gamboge of Ceylon — resin 

 75-5, arabin 18-3, cerasin 0-7, water 4-8. He considers the resin to 

 be the active agent, and concludes from the composition that the 

 Siam cakes are not natural productions, but a manufacturing product, 

 and that the gamboge of Ceylon, being free from woody matter, has 

 the same composition as the gamboge of Siam, and both are conse- 

 quently from the same plant. — L' Institute 166. 



2. Canella Bark. — According to Nees von Esenbech, there are 

 three trees from which canella is derived ; viz., Laurus china 

 momitm. affording the canella of Ceylon ; Lauras cassia producing 

 the Chinese canella, and the Lauriis Malahathricay the bark of 

 which is nothing else than the Cassia lignea. — Guibourt Hist, 

 des drogues, vol. ii. 



3. Conein. — According to he experiments of Geiger, Christison, 



