The injurious effect of dry heat in inhabited rooms is quite generally known, and different methods have been suggested for moistening the air. To test the effectiveness of these methods, J. Melikow, of St. Petersburg, has estimated the quantity of moisture in the air of different rooms by means of August's psychrometer, and also tested the different methods of increasing the moisture. He arrived at the following results, which are of decided practical value:

1. When large and small open vessels filled with water are placed in the room, they do not increase the moisture of the air at all.

2. Tubs of water of the same temperature as the room and parlor fountains have very little effect.

3. When hot air is used, open vessels of water placed over the pipes have no effect at all.

4. Wolpert's revolving wheel increases the moisture but slightly.

5. The Russian tea machine and the steam pulverizer (atomizer) are effective but only for a short time.

6. Wet hand towels suspended in a room are insufficient.

7. Of all the methods tested, the most efficient seemed to be to hang up a number of wet cloths on a winch or some contrivance that permits of turning them, so as to hasten their giving out moisture to the air. Med. Zeitung.

[The following article is from the June number of the American Naturalist, edited by Prof. A. S. Packard, Jr., and Prof. E. D. Cope. Published by McCalla & Stavely, Philadelphia, Pa.]