192 REPORT — 1860. 



What our views, however, of the original constitution of matter may be, 

 is a point of less consequence than what are the conclusions in geology to 

 which we are conducted by observation and experiment. The general con- 

 clusions to be drawn from the foregoing researches seem to be these : — 

 That no theory of the earth consists with the phenomena, which does not 

 take into account a heat of the surface once amounting to redness; — that 

 the most prominent chemical and crystalline compounds which laid the base- 

 ment of the earth's crust, and continued to penetrate it, as far as into the 

 tertiary strata, have disappeared in the present eruptive system ; — that the 

 nature, force, and progress of the past conditions of the earth cannot be 

 measured by its existing conditions ; — that to deduce accurate inferences in 

 the sciences of observation, the attention requires to be directed less to gene- 

 ral analogies than to specific and essential distinctions. 



EXPLANATION OF PLATES. 



PLATES IV. & V. 



Section, and Plan, of the furnace in which the deposits lay for 15 years, the number 

 of each deposit, external to the boxes, being marked on the plan. 



PLATE VI. 



Fig. 1 (Plan No. 4). Tile copper .5 in. X 2} in. X f in. coated with lamina? of dark, 

 red, crystallized oxide of copper, alternating with white and yellow crystallized prot- 

 oxide of lead, and with a pink intermixture of crystallized oxides of copper and lead 

 covered with sand indurated, but not vitrified, by protoxide of lead. 



a. Twisted filaments of metallic copper. b. Crystals of red oxide. 



bb. Laminae of crystallized red oxide of copper alternating with protoxide of 



lead, and mixture of oxides of lead and copper, 

 c Particles of metallic copper. cc. Golden metalline spot. 



Fig. 2 (Plan No. 3). Pig lead, 4.| in. X 3| in. X 2i in. View of upper surface, show- 

 ing green and yellow double oxides of lead and copper, with spots of metallic copper. 



d. Cavity from which lead has sublimed. 



e. Spots of metallic copper. 



f. Double oxides of lead and copper. 



PLATE VII. 



Fig. 3 (Plan No. 3). Pig lead, vertical section, showing exterior and interior 

 seams of mixed oxides of lead and copper, green, yellow, and red, with spots of me- 

 tallic copper. 



g. Red oxide of copper between lead and indurated sand. 

 h. Spots of metallic copper in the interior of the lead. 



i. Oxide of copper and lead. kk. Lead hardened by disseminated oxide. 



Fig. 4 (Plan No. 4). Enlarged section of part of fig. 1, showing threads of metallic 

 copper. 



Fig. 5 (Plan No. 4). Part of fig. 1 ; enlarged view of pink mixture of crystallized 

 oxides of copper and lead, with spots and threads of metallic copper. 



PLATE VIII. 



Fig. 6 (Plan No. 2). Block tin, 3 in. X 2 in. X 1 in., with a coat of transparent cry- 

 stallized deutoxide from fin. to A inch thick. 



I. Striated surface of metal beneath oxide. 

 m. Crystals of deutoxide, transparent and colourless. 

 Fig. 7 (Plan No. 1). Zinc bar, in indurated sand, fractured, showing a surface 

 partly metallic, partly crystalline. 



n. Spicule of sublimed metal. o. Seam of metal. 



Fig. 8 (Plan No. 1). Showing cavernous face of oxide of zinc with crystals of do. 

 p. Cupped hollows set with crystals of oxide of zinc, out of which globules of 

 metal have sublimed. 



