CONTENTS. 
Aut- XI. Account of the Strata at the Diamond Mines of Mai- 
livully. By the late Dr James Anderson of Ma- 
dras, „ . „ 
XII. Account of some Single Microscopes upon a new 
construction. By David Brewster, LL.D.F.R.S. 
Lond., and Sec. R. S. Edin. - 74 
XIII. Some account of a suspended Plant of Ficus Aus- 
tralis, which has grown for eight months without 
earth in the Stove of the Botanic Garden at Edin- 
burgh. By Mr William Macnab, Superinten- 
dant of the Garden, Communicated by the Au- 
thor, , 7 j 
XIV. Description of a new method of forming Crucibles. 
By Mr Charles Cameron. Communicated by 
the Author, - - - 81 
XV. Account of the Great Cavern of the Giiacharo, By 
Baron Alexander de Humboldt, - 83 
XVI. On the fluctuating Sensibility of the Retina. By 
Mr Thomas Smith, Surgeon, Kinguissie, Com- 
municated by the Author, - 92 
XVII. Notice respecting a Singular Structure in the Dia- 
mond. By David Brewster, LL. D. F. R. S. 
Lond. and Sec. R. S. Edin. - 98 
XVIII. Notice regarding the Submarine Remains of a 
Grove of Fir-Trees in Orkney. Contained in a 
Letter from W. G. Watt, Esq. of SkaiU, to Mr 
Stevenson, Civil Engineer, - 100 
XIX. Account of the Correspondence between Mr Park 
and Mr Maxwell, respecting the Identity of the 
Congo and the Niger. By the Rev. William 
Brown, D. D. Minister at Eskdalemuir. Com- 
municated by the Author, - 10^ 
XX. Notice of a Collection of Rare Plants from India, 
presented to the Botanic Garden of Edinburgh, 
by Dr Wallich of Calcutta and Lieutenant-Colo- 
nel Udney Yule, C. B. with remarks on the best 
method of introducing Tropical Species into Eu- 
rope. By John Yule, M. D. F. R. S. Ed. and 
M.W. S. - - . - IH 
XXI. Account of Three New Species of Lead-Ore found at 
Leadhills. By H. J. Brooke, Esq. F. R. S, Lond. 
M. G. S. &c. Communicated by the Author, 117 
