Page:Popular Science Monthly Volume 12.djvu/525

Rh the basin in which it is found the surface is sand, either white and barren or brown and loamy, with occasional ridges or distributions of limestone. Next below this is segregated limestone, hard and approaching crystallization, the interstices filled with light-brown tenacious clay, followed by compact light-red sandstone of various thickness, fading in color and consistence until it touches the water and merges into quicksand. On the lowest flats fissures occur in the limestone; the orifices are very small and irregular, but reach to the underlying quicksand.. The following is the result of an analysis of this mineral caoutchouc:

Living Out-of-Doors.—A retreat for consumptives should possess above all things an equable temperature throughout the year, so as to favor living out-of-doors at all seasons. The advantages possessed in this respect by the Hawaiian or Sandwich Islands can hardly be surpassed. The climate there, says Dr. H. B. White, in the "Proceedings" of the Kings County Medical Society, in its average temperature and in equability, may be said to be perfect. These islands are situated between 19° and 22° north latitude, where the trade-winds blow with great regularity about ten months of the year. Though lying within the tropics, the temperature is modified by the constant fresh breezes. In the language of Hawaii, there is no word for weather. The most favorable situations for consumptives are, according to Dr. White, Honolulu, Lahaina, Ulepalekua, Kailua, and Ewa. The main temperature on and near the coasts is 75° to 79° for the warmest months, and 72° for the coldest. During Dr. White's four years' residence at Lahaina the maximum was 84°, and the minimum 61°, while the general average for the summer months was 82° for mid-day, and about 72° for the winter months. By ascending the mountains a few miles inland, almost any degree of temperature can be obtained.

Improvements in Photography.—Both the chemist and the practical photographer will be interested in a communication from Mr. M. Carey Lea, published in the American Journal of Science, for July on certain new means of developing the latent photographic image. It has been supposed that only very few bodies possess this singular power of developing, but Mr. Lea's researches show—1. That, on the contrary, such bodies are very numerous; 2. That, contrary to what has been generally held,