Artificial stone is also manufactured from the granulated slag, and used for building purposes, furnishing warm dry houses of handsome appearance.
When stones for building with enamelled surfaces are required they are obtained in some parts of Europe as follows:—The unburnt bricks are covered with granulated slag, and after drying are burnt in a furnace where they do not come in contact with carbon. The stones are completely glazed, and according to the different kinds of slag used are tinted of different colours. This operation is also employed advantageously with tiles, pipes, and earthenware.
If, in the preparation of fire-proof bricks, a certain proportion of mixture of clay and granulated slag be added to the mixture, very hard and durable fire bricks are obtained. These have been tested in a brass furnace, and experiments are being tried as to their
applicability to building puddling furnaces. This granulated slag may also be advantageously used for manure. Blast furnace slag has also been drawn out in fine threads or filaments, furnishing the so-called ‘furnace wool.’ This substance, being a very bad conductor of heat, has suggested various household and other uses. A cheap and valuable cement, said to be equal to Portland cement, has been prepared from the finely granulated slag, which will also resist well the action of acids.
Mr Britten in 1876 patented a process for the manufacture of glass from blast furnace slag. Large works for the purpose of carrying out this invention, under the title of ‘Britten’s Patent Glass Company,’ have been erected at Finedon in Northamptonshire, and are, we believe, successfully worked in manufacturing glass bottles.
The method consists in removing molten slag in a ladle from the blast furnace, and pouring into a Siemen’s furnace, when certain amounts of carbonate of sodium and silica are added, depending upon the quality of the slag used, and of the glass required.
SLATE. The excellence of this material for water cisterns deserves a passing notice here.
Irish slate (Lapis Hibernicus) is an argillaceous mineral, said to contain iron and sulphur, found in different parts of Ireland. It is a common remedy, among the vulgar, for internal bruises, taken in a glass of gin.
SLEEP. During the period of our waking hours the exercise of the animal functions entails a waste or destruction of tissue in the organs performing them, which, unless duly repaired, would soon lead to the enfeeblement and consequent failure of the powers of the organs themselves. For the animal economy therefore to be maintained in a state of efficiency the repair of the reduced tissues is a necessity; and this essential condition is effected by the agency of sleep, during which respiration, circulation, digestion, &c., continue to be carried on simultaneously with assimilative processes which end in the regeneration of the impaired tissue.
A proper amount of sleep is therefore as great or even a greater necessity than a proper supply of food; and any one failing to obtain it soon perishes of exhaustion. Thus it is that any great mental emotion—such as intense remorse, grief, anxiety, or the depressing effect of a reverse of fortune—so frequently expedites death. Like Macbeth “it murders sleep,” one of the great needs of man’s existence.