TRANSACTIONS OP THE SECTIONS. 93 



but also in some degree chemical, a small portion of sulphide of mercury being 

 found in the scum, whUe the gold extracted contained a much larger proportion 

 of copper than is usual mth Australian gold. The Australian miners appeared to 

 have hit on no economical mode of separating the gold from pyritous quartz, so as 

 to avoid this loss. 



On a Specimen of Meteoric Iron from Mexico. By Professor Tennant. 



On the Cohesio7i-Fi(jures of Liquids. By Charles Tomlinson. 

 Eegarding solution as a case of adhesion, the author showed that when a drop of 

 an independent liquid («. e. not a solution) is placed on the surface of another in- 

 dependent liquid, such as water, a struggle takes place between them. The par- 

 ticles of the drop endeavour to maiutain their cohesion, the adhesion of the surface 

 tends to overcome it; hence a well-defined figure, named by the author a cohesion- 

 Jigure, and regarded as the resultant of the cohesion of the liquid, its density, and 

 the adhesion of the surface. For example, if a drop of oil of lavender be gently 

 delivered to the surface of water in a chemically clean glass, about 3^ inches in 

 diameter, it is spread out by the adhesion of the surface into a weU-defined film ; 

 cohesion then endeavours to reassert itself, and a struggle takes place between the 

 two forces, the result being a beautiful complicated pattern resembling Carrigeen 

 moss. The cohesion-figures of other oils, fixed and volatile, of creosote, ether, 

 alcohol, naphtha, &c. were shown experimentally, or in the form of large diagrams. 

 In order to produce these figm'es, the glass vessels and the water must be chemically 

 clean. The figures present a variety of novel and beautiful effects, both as to form 

 and colour, and are likely to prove highly suggestive to the pattern-designer. 

 Moreover, the forms being tyjDical of the substances, a ready means is thus afforded 

 of detecting adidteration. 



On the Composition of Crystallized Moroadte, from Jumillo, near Alicante. 



By Dr. Voelcker, F.C.S. 

 Beautifully crystallized moroxite occm-s in lar^e quantities at Jumillo in Spain. 

 Selected crystals of this mineral, analysed by the author, give the following re- 

 sults : — 



Water of combination -298 



Phosphoric acid 87-024 



Lime 52-954 



Magnesia •269 



Oxide of iron 1-170 



Alumina -943 



Oxides of cerium (impure oxides) 1-790 



Fluorides of sodium and potassiimi 1-033 



Chlorine trace 



Silica -340 



Fluorine and loss 4-179 



100-000 

 These constituents, combined with each other, give — 



Water of combination -298 



Tribasic phosphate of lime | i,!:;^ ^^'?"| 



80-218 



Mag-nesia -269 



Oxide of iron 1-170 



iVlumina -943 



Oxides of cerium 1-790 



Fluoride of sodium and potassium 1-033 



Silica -340 



Fluoride of calcium 13-489 



99-550 



