92 REPORT— 1869. 



sections, as Coralliue, Tied, nnd Fluvio-mariue, Szc, all these sections bcinp: only 

 different parts of one continuous deposit, occurring generally in estuarine or 

 shallow water, and subjected to gradual changes of temperature Sec, by ■which 

 the character of the fauna was gradually altered, and that it thus presents a 

 striking instance of that continuity, not only of life, but of lithological forma- 

 tion, which we find more or less exemplified in all geological strata. 



(hi the Action iqwn Earthy Minerals of Water in the Form of heated Steam, 

 urged by wood fuel, an experiment reported to the Association at its 

 Meeting at Glasgow in 1840. By Julius .Jeffreys, F.R.S. 



The experiment was made at Futtehgurh in India, in 1830, its object having 

 been to determine the action of water in the form of steam at an intense heat, as 

 a solvent of minerals insoluble in it at lower temperatures. 



The instrument employed was a cylindrical kiln surmounted by a cone, and 

 interiorly about 30 feet high and 16 in diameter, employed for vitrifying stone- 

 ware. 



Four furnaces, 8 feet long and 4 wide, projected radially from the exterior of 

 the kiln, and heated it through fire-throats about 3 feet wide and a foot high, 

 each inrush of fl.inie being allowed in part to flow towards the centre of the kiln, 

 in part laterally, but the larger portion being turned upwards by dwarf chimneys 

 in the kiln, built against its sides. These chimneys were as wide as the throats, 

 say a yard, and about 18 inches from front to back. 



For the experiment, a pit was dug between each furnace and the kiln, about 

 4 feet wide, .5 deep, and 10 inches broad from front to back. A fire-brick bridge, 

 or low wall, kept the fuel from falling into the pits. These pits were kept filled 

 with water. 



Specimens of minerals, rock, and stones, and of ceramic ware and fire-brick 

 ■were ranged in the fire-chimneys, or fire-bags as they are called by potters, also 

 on the fioor of the oven, and on the shehes on which were placed a few imbaked 

 specimens of the stoneware (chiefly bottles for mineral waters), for firing which 

 the kiln was usually employed. 



It should be mentioned that the arched shelves were made of a highly aluminous 

 and contractile clay, practically infusible, made into bricks (in a manner for de- 

 scribing which space is not here afforded) so dense that any fragments of them 

 would scratch glass readily ; whereas the fire-bags were built with an inferior and 

 much more porous and siliceous brick, nearly similar to English Stoui-bridge, 

 specimens of these being amongst them. 



The fuel was wood of mango, dawk, and a peculiar light wood from the Tewai 

 Jungle. These woods abounded in alkali. They gi-ow in the valley of the Ganges, 

 the soil of which is disintegi-ated mica and felspar. 



The ordinary action of high firing with this fuel was to slightly melt the sm-faces 

 of the fire-bags into a glassy coat, sometimes ■v\dth tears of glass trickling do-wn, 

 bm-ning a little slag ; but the dense shelf-bricks were but slightly affected by the 

 alkali. 



After an intense firing of more than forty-eight hours, during which the water 

 had to be renewed in the pits, on opening the kiln all the glazing had disappeared, 

 and the minerals in the fire-bags had been reduced in volume. Their walls were 

 eroded to a depth varjing from one to two inches. The specimens of ware on the 

 lower shelves were in some places eaten through. The xmbaked stoneware was 

 fully ^itrified, but the micaceous " slip " glaze on the surfaces, ordinarily a glossy 

 bro'wn coat, was dissipated, the body of the ware being also eaten into. The dense 

 brick-shelves were but slightly affected. The specimens of this ware on the 

 uppermost arch of the kiln, where the heat was not above a full red, were in the 

 usual state of any ware placed there, viz. under-fired in the body, and coated with 

 a rich brown glaze, the heat sufficing to melt it. But the surfaces, especially the 

 shoulders of the ware, were covered with a mineral hoar-frost — a loose incrusta- 

 tion evidently deposited before the glaze had melted, and under which the ware 

 had contracted in hardening, so as to raise up the frosty coat more clear of the 



