A detailed description of the Blechynden boiler of the steam yacht Scud built by J. S. White of Cowes. The boiler primarily consisted of three chambers or drums, of the simplest form, the upper or steam chamber, which was circular, being connected to two lower or water chambers (which were nearly circular in shape) by two groups of slightly curved water-tubes, all bent to the same curvature, thus providing for their expansion and extension under heat, as any bending that took place had its direction defined by the initial curvature given to the tube in the first instance, this curvature in no way interfered with the proper examination of the tubes interiors. The boiler illustrated worked at a pressure of 150-200 pounds per square inch. The diameter of the upper chamber was 2 feet 2 inches, and its length 12 feet 3 inches; the lower or water chambers were 12 inches in diameter. The boiler had a tube-heating surface of 1,200 square feet; the diameter of the galvanised steel generating tubes was 1 inch whilst that of the four down tubes was 4.5 inches. The grate surface was 24 square feet.