1908] Sanitary Conditions of Houses 35 



if possible, to be to the south. The direct rays of sunhght are 

 so active in promoting rapid metabolism in tissues, as observable 

 in a plant placed in a south window, as compared with a north 

 window, that nothing more need be said to illustrate the fact. 

 Hence, we should get in all the sunlight possible. 



As regards lighting, the amount of light required is large 

 not only fo: sanitary purposes, but also for lighting up all parts 

 of a room. One daily sees a householder either wishing, himself, 

 or yielding to the desire of an architect to produce a so-called 

 aesthetic effect by small, low. mullioned and small diamond-shaped 

 panes in windows. It is absolutely wrong and only excusable 

 if at all in a church, not in living or working rooms. A good rule 

 is that the amount of the area of windows, placed as near the 

 ceiling as possible, should be at least 1-5 of the floor area of a 

 room, and direct sunlight ought to reach the farthest side of 

 a room. Modern science, however, has done something to 

 increase the diffusion of light by ribbed glass and luxfer prisms. 



Having now got our house built as a protection against cold 

 and well lighted, we turn to the interior and enquire how we are 

 going to maintain its air in such a condition of normal purity, 

 moisture and temperature as will conduce to the highest degree 

 of health in the inmates. I assume, of course, that the house has 

 up-to-date plumbing and water supply Now, as stated in mv 

 lecture last year, the problem is how to maintain the air in such 

 as tate that the carbonic acid will not be more than 5 in 10,000 

 parts, also to see that the relative humidity is about 70% and 

 that the temperature is 60° to 65° F. It seems simple, but in a 

 practice it is found to be even in a small house a relativelv 

 complex problem. First, as regards the temperature, this mani- 

 festly depends upon the kind of heating apparatus. We have 

 practically two kinds for everyday houses, viz., hot air furnaces, 

 and hot water pipes, and both depend for their success upon their 

 ability to transmit to the air of different rooms an adequate 

 amount of heat economically. Almost all know that to conduct 

 warm air to the side of the house against which a strong wind 

 is blowing is very difficult, if other pipes are present to lead the 

 warm air elsewhere. On the other hand, hot-water pipes will 

 carry heat in an amount directly in proportion to the extent of 

 pipes in a room. It is further true that a well-constructed 

 hot-water furnace will transmit into the flow of water through it. 

 more heat units than could be transmitted to the air surrounding 

 a hot-air furnace. 



But apart from these two economic advantages to set against 

 the greater one of the first cost of the hot- water svstem, there 

 are several other very important items as regards the effect of 



