Page:Popular Science Monthly Volume 46.djvu/165

Rh quick co-ordination of muscles, for pluck, perseverance, and sel-fpossession, far more than for mere strength, and are legitimate training, therefore, for girls, so far as they are qualified to undertake them.

A more valid objection to the gymnasium is that the exercise must be taken indoors, but this is largely overbalanced by the advantages of system and purpose in the course, and is reduced to its minimum by the fact that a well-ordered gymnasium is cool, clean, and well ventilated. The suggestion often proffered that domestic work offers as good a field f-or exercise for girls is not, in the writer's opinion, tenable. An atmosphere of dust is not an ideal one for physical training, and the elements of system as well as of physical recreation are lost in this scheme, for few households could arrange their economy so as to combine the schoolgirl's leisure with their own convenience, while the drudgery of the employment would cause it to be abandoned whenever possible.

It is not our intention to claim that the gymnasium is the permanently ideal place for every sort of physical training or athletic sport for girls, but only that it does at present offer the greatest good to the greatest number of our city girls in the direction of their physical development and recreation. An out-of-door inclosure for games and sports in pleasant weather would prove a great addition to its advantages. It does not seem an impossible plan for the private schools of our city to co-operate in establishing such an out-of-door playground as this, with an instructor in games and sports, and hours arranged for each school department. Such a ground would prove a practical and useful extension of our too limited park life.

an apparatus sensitive enough to measure changes in temperature amounting to only a millionth of a degree, Prof. S. P. Langley has located exact more than two thousand lines in the infra-red spectrum, in which two thirds of the sun's radiation is contained, and has succeeded in extending the spectrum to six times the length of the photographic spectrum. He has tested his instrument in the region of the sodium lines, and found it could not only divide these, but could detect the nickel line between them. By a special device, depending on the use of a cylindrical mirror, he was able to convert automatically the galvanometer tracings into a linear spectrum. He thought the extended spectrum would be of use in forecasting the weather, because it contained a rain band; moreover, the greater part of the lower spectrum seemed to be due to telluric causes. In the discussion of the author's paper in the British Association, the chairman of the Physical Science Section spoke of it as the most important paper that would be communicated to the section. Prof. Lockyer said that the work had done for the lower spectrum what Kirchhof had done for the visible rays. Lord Kelvin admired the marvelous precision of Prof. Langley's method, and the skillful way in which it was carried out.