In answer to an inquiry about these, the following is appropriate: "The Central-blatt der Bauverwaltung describes a patented composition made at a factory in Stargard, Pome-rania, which has for some years past been used with perfect success on the Berlin-Stettin railway for wall copings, water tables, and similar purposes requiring a water-proof coating. The material is composed of coal-tar, to which are added clay, asphalt, resin, litharge, and sand. It is, in short, a kind of artificial asphalt, with the distinction that it is applied cold, like ordinary cement rendering.

The tenacity of the material, when properly laid, and its freedom from liability to damage by the weather are proved by reference to an example in the coping of a retaining wall which has been exposed for four years to the drainage of a slope 33 feet high. This coping is still perfectly sound and has not required any repair since it was laid down. Other works have proved equally satisfactory. In applying this mortar, as it is termed, the space to be covered is first thoroughly dried, and after being well cleaned is primed with hot roofing varnish, the basis of which is also tar. The mortar is then laid on cold, to the thickness of about three-eighths of an inch, with either wood or steel trowels, and is properly smoothed over. If the area covered is large, another coating of varnish is applied and rough sand strewn over the whole. The waterproof surface thus made is perfectly impregnable to rain or frost, and practically indestructible. The cost of the material laid is estimated at not more than ten cents per square foot, and it is stated that this price can be reduced, by at least two cents for large quantities put down by experienced workmen."