The human body and health Volume 3; an elementary text-book of essential anatomy, applied physiology and practical hygiene for schools - Alvin Davison, Paperback

• Release Date   5/19/2012
• ISBN-13   9781236258670 | 978-1-236-25867-0
• ISBN   1236258673 | 1-236-25867-3
• Format   Paperback
• Author(s)   Alvin Davison
• This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1908 Excerpt: ...dioxide in the same way that people do. Four half-inch holes, bored in each end of a box with a capacity of 400 cubic inches, are fitted with corks and a pane of glass serves for one side. By removing the corks from one group of holes at a time, it is easy to determine which supplies the larger amount of air, as the candle flame goes up and down according to the amount of oxygen and carbon dioxide present. With all the corks in, the candle is extinguished in one minute. If two corks on the same end at the top are removed, the candle will burn two minutes. The removal of the two corks at the top in both ends allows the candle to burn three minutes, while if the corks are all in except two in the same end, one being out at the top and the other at the bottom, the candle will continue to burn until consumed. This is clear proof that only two openings, one low and one high, on the same side of a room afford Fig. 106.--Diagram showing how to open the windows so that all pupils may have fresh air. The course of the air currents were determined by smoke and the brightness of the candles burning in different parts of the box. i, inlet for air. o, outlet for foul air. The dotted line is the level of the heads of the pupils. HOW TO VENTILATE 159 better ventilation than twice as many opening at the top. When a basement heater is used, plenty of fresh air may be furnished by leading it through a duct from the outside to the furnace to be heated and sent to the rooms above. On this account hot air is much more healthy than steam for heating purposes unless a special arrangement is made for supplying fresh air or drawing the impure air out by means of a fan. When air is forced into a room, it should enter near the ceiling, and an opening for the escape of the impure air ...