STEAM HE A TIN G. 739 
of giving thorough ventilation, but it is the most expensive in fuel. The close 
stove is highly advantageous in point of economy, where there is little ventila- 
tion, and as this is apt to be the rule, it is perhaps the least healthful of all methods 
as generally applied. Both of these methods become costly in attendance as 
well as in fuel when the heating of dwellings of many rooms is required, and are 
inapplicable to large structures and public buildings as they are now constructed. 
The hot-air furnace system is of all the most difficult to manage, so far as uni- 
formity and control of temperature is concerned. The danger from fire, the 
dust, the defective ventilation, and the impracticability of heating more than a 
limited space by a single hot-air furnace are other defects inherent in this system. 
Steam heating involves greater first cost in apparatus than any other system. 
When this cost and the cost of attendance and repair are taken for a series of 
years, however, it is conceded that there is but Uttle choice between hot-air 
furnaces and steam-heating apparatus as regards economy. 
The special advantages of steam heating are : 
1. The almost absolute freedom from risk of fire when the boiler is outside 
of the walls of the building to be heated, and the comparative immunity under 
all circumstances. 
2. When the mode of heating is the indirect system, with box-coils or 
heaters in the basement, a most thorough ventilation may be secured, and it is 
in fact concomitant with the heating. 
3. Whatever may be the distance of the rooms from the source of heat, a 
simple steam-pipe of small diameter conveys the heat. From the indirect heaters 
underneath the apartments to be heated, a vertical flue to each apartment places 
the flow of the low heated currents of air under the absolute control of the occu- 
pants of the apartment. Uniformity of temperature, with certainty of control, 
may be thus secured. 
4. Proper hygrometric conditions of the air are better attained. As this 
system supplies large volumes of air heated only slightly above the external tem- 
perature, there is but little change in the relative degree of moisture of the air 
as it passes through the apparatus. 
5. No injurious gases can pass from the furnace into the air flues. 
6. When the method of heating is by direct radiation in the rooms, the 
advantages of steadiness and control of temperature, sufficient moisture and 
good ventilation, are not always secured; but this is rather the fault of design, 
since all these requirements are quite within the reach of ordinary contrivances. 
7. One of the conspicuous advantages of steam heating is that the most 
extensive buildings, whole blocks, and even large districts of a city, may be 
heated from one source, the steam at the same time furnishing power where 
needed, for ventilation or other purposes, and being immediately available also 
for extinguishing fires, either directly or through force pumps. 
It is only to be remarked, finally, that the most thoughtful among our physi- 
cians and sanitary advisors realize with anxiety the fact that there is a growing 
abuse of all these systems, except the open fire, in providing too much heat and 
