We give herewith perspective and sectional views of an improved portable shower bath, recently patented by Mr. James E. Vansant, of Covington, Ky. It consists of a spherical vessel, having at the bottom a supporting rim which admits of setting it on the floor when occasion requires. The top is provided with a screw cap, perforated with numerous small holes for discharging water in fine streams. In the center of the cover there is a filling tube, which extends nearly to the bottom of the vessel. A float is provided to indicate when the vessel is filled, and shot contained in the two side tubes serves as ballast to keep the device either in an upright or inverted position. [Illustration: Fig. 1.--VANSANT'S PORTABLE SHOWER BATH.] [Illustration: Fig. 2.--SECTION OF SHOWER BATH.] The vessel is pivoted in a light jointed frame that admits of hanging it up or setting it down. In use it is tipped by means of the cords attached. * * * * * MINES AND RAILROADS OF LEADVILLE. _To the Editor of the Scientific American:_ Nearly every person interested in geology sets up a theory of his own with regard to the carbonate deposits of Leadville, immediately on arriving in this famous district. There is, however, but one theory which has been generally adopted by scientific men, formulated by W. S. Keyes, General Manager of the Chrysolite Iron and Little Chief Mines, and substantiated by the mute testimony of the fossil remains that fix the geologic data. The theory is substantially as follows: A shallow sea overspread this entire region. An even bed of limestone, dolomitic, was formed by the myriads of shell-fish that subsisted in this shallow sea. From some natural convulsion the waters flowed off, leaving the sedimentary deposits. Subsequently the porphyritic rock flowed over the surface in a pasty mass, covering the limestone. There then followed two processes of ore making. The first was through the mineralizing action of heated and ore depositing waters, coming up out of the depths, and impregnating and permeating the hanging and foot walls of the contact. No free oxygen was contained in these waters; neither did they carry any chlorides or chlorobromides, wherein consists the present richness of Leadville's ores; but in the first process the ore was entirely in the form of sulphurets.