When we turn from viewing the surrounding scenery and begin to examine particularly each separate formation, we find near the center of this sublimated field a blue spring, brilliant as a sapphire, and clear as a diamond, with a deep and irregular rim all around it, as if nature had made an effort to retain its beautiful waters. This spring is fifteen by twenty feet in area, and is in a state of constant agitation. The sides and bottom of the basin are formed of pure white travertine, while the varying depths cause the water to appear all shades between a deep peacock-blue and a light nile-green. Issuing at a temperature of 165°, the water contains a considerable amount of gas, which escapes at the surface of the pool, thus causing the flow to rise in the form of a little dome, while a pulsating movement is imparted which sends out waves that ripple across the water and curl over the shallow rim of the bowl, filling other basins along its course. These terraced overflow basins, thus formed, are a most striking feature of the springs. No description can do justice to their beauty, for neither the delicate fretwork of their walls, the frosted surface of the glistening deposit, nor the brilliant colors of the pools and rivers can be adequately described. In many places the overflow is in thin sheets and little cascades, while yellow, sulphur-coated threads of algæ are abundant, though they do not impart their color to the water, for the exquisite blues and greens of the hottest basins are due solely to the varying depths of water. On the other hand, the bright lemon, red and green shades of the cooler pools are entirely vegetable in their nature, and due to the presence of algæ lining the basins and striping their outer walls. The upper basins are generally shallow, because of the rapid deposit of lime, but this deposition occurs after the overflow, thus forming what is called the Marble Basins, after which, the water being somewhat cooled, the deposit is slower. Accordingly, we find that the lower slopes are exquisitely fringed with slender stalactites and pillars, forming the beautiful Pulpit Basins as shown in the illustration. The Government has expended large sums of money in making roads through the most interesting sections of the park, and over these we pursued a greater part of our way in reaching the places which we desired to photograph. A stage runs through the park, in which visitors may make the tour in six days, but for manifest reasons we traveled by private conveyances, camping out as often as we took quarters at the several hotels located at convenient distances along the route. ------------------------------------------------------------------------ [Illustration: