Page:Popular Science Monthly Volume 88.djvu/418

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��Poj)nJar Science Monthly

���A large hospital for infants has recently been equipped with a number of rooms with glass walls, so that without entering the rooms nurses may observe the babies as easily as if they were so many fish in an aquarium

��Babies in Glass Cases

T\\'0 years ago the Hebrew Infant Asylum at Kingsbridge Road and University Avenue, New York, adopted the plan of using glass cases for ba- bies admitted to the observation build- ing. As a result the children may be ob- served without the necessity of entering their rooms.

Each child is supplied with its own utensils, to\vels, bath, etc. If one baby develops a communicable disease it is impossible for it to give it to another. This is the first building of this kind to be erected in the United States. The idea was taken from some European in- stitutions and adapted to the needs of this asylum. There are glass chambers enough to accommodate twelve babies ranging in age from a few days up to one and a half years.

Why Is the Sun Hot?

IF we could build up a solid column of ice from the earth to the sun, two miles and a half in diameter, spanning the intervening distance of ninety-three million miles, and if the sun should con-

��centrate his entire power upon it, it would dissolve in a single second, according to a calculation made by Professor Young. To produce this enormous amount of heat would require the hourly burning of a layer of anthracite coal more than nineteen feet thick over the entire sur- face of the sun. If the sun were com- posed of solid coal and we derived our heat from the burning of that coal the sun would burn out in less than five thousand years. Since the earth is mil- lions of years old the sun can not be burning. Its heat must be generated in some more persistent Avay.

The great German physicist Helmholtz was the first to explain satisfactorily what keeps the sun hot. The sun is not burning ; it is heated to the glowing point, like a piece of white hot iron. Helm- holtz found that if w^e suppose the sun to be contracting by only two hundred and fifty feet a year we would receive our present amount of heat. In other words heat is being literally squeezed out of the sun. Professor Newcomb estimated that when the squeezing process has contin- ued for about seven million years, the sun will be one half its present size.

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