JOURNAL OF MICROSCOPICAL SCIENCE. 



DESCRIPTION OF PLATES XV, XVI, 



Illustrating Dr. Ord's paper on " Molecular Coalescence," 

 and on the Influence Exercised by Colloids upon the 

 Forms of Inorganic Matter. 



PLATE XV. 



"Forms observed in thirteen sections of the gelatin plug used in the 

 first exjjeriment. 



rig. 1. — First slide, from calcic end. 



a. Large tables of oxalate of calcium seen sideways ; b, the 

 same, fiat ; (?, smaller tablets ; r/, compound tablets. 



„ 2. — a. Homogeneous dumb-bell formed within large tablet ; b, c, d, e, 

 dumb-bells and allied spheroidal homogeneous bodies. 



„ 3. Various forms of coalescence-bodies, showing their relation to 

 tablets. (Slide 2.) 



„ 4. — Tablets and spherules of a new series ; the spherules (a, b, and c) 

 growing to large rounded, fibrous rhoinbohedra, composed of 

 calcic carbonate ; the tablets growing, further on, to " wheat- 

 sheaves." (Slides 3 to 7.) 



„ 5. — Formation of " wheatsheaves" from the thick tablets. (Slides 8 to 



13.) 

 „ 6. — Flattening and feathering of octohedra. (Slide ]3.) 



PLATE XVI. 



„ 1. — Forms assumed by calcic oxalate in gelatin, acetic acid being pre- 

 sent in excess. 



„ 2. — Oxalic acid in excess of calcium salt. Series constructive of 

 flattened octahedron. 



„ 3. — Oxalic acid in excess. Series of dumb-bells from calcic end, where 

 they are homogeneous and rounded, to oxalic end, where they 

 are crystalline (" wheatsheaves"). 



„ 4. — Oxalic acid in excess. Octohedra passing into much facetted 

 tablets. 



,, 5. — Thinning of tablets on calcic side of plug. 



„ 6. — Oxalate of ammonium and calcic chloride. Form of " wheatsheaf " 

 observed in oxalic region of plug. Note, tliat I have, since 

 this was drawn, observed similar forms twice in urine. 



„ 7. — Comparison of forms observed in magnetised plug with those 

 formed at the .same time, all other conditions being perfectly 

 equal, in non-magnetised plug. The large tablet-shaped bodies 

 were formed in the magnetic arc. 



„ 8.— Oxalate of copper, as deposited in gelatin. 



