

HOtTSE VENTILATION.] 



UNDULATORY FORCES. HEAT. 



33 



preventing the escape of heat ; and the opening of the 

 fire-grate into the chimney becomes almost the only 

 means by which the foul and heated air can escape. As, 

 however, this opening rarely extends to one-half the 

 height of the apartment, it follows, as a matter of course, 

 that any ventilation which is effected is of the most im- 

 perfect nature. The causes of the vitiation of air in any 

 room are so various, and so dependent in many instances 

 on accidental circumstances, as almost to defy enumera- 

 tion. We may, however, refer to some which are found 

 active in the majority of cases such as the products 

 of breathing, and of the combustion of gas, oil, and 

 candles. 



The constitution of the atmosphere is such as to afford 

 a gas, called oxygen, which, by combining with the char- 

 coal of the food during respiration, is expired in the form 

 of carbonic acid gas on the expiration of the breath. In 

 fact, the process carried on in the lungs of man is exactly 

 identical, in its chemical character, to that which we ob- 

 serve in the combustion of the coal in our furnaces or 

 domestic fire-places. The food we partake of is converted 

 into a peculiar substance, called chyle; and this being 

 absorbed by the vessels of the stomach, becomes converted 

 into blood. The blood thus produced is conveyed, by 

 means of vessels, to the surface of the lungs ; and the 

 charcoal it contains is gradually consumed, and its 

 latent heat set free. The charcoal is thus converted into 

 carbonic acid, which is composed of sixteen parts of 

 oxygen to six parts of charcoal, in every twenty-two parts 

 of gas produced. It follows, therefore, that we are con- 

 tmusllv casting a poison into the air at each expiration 

 of tb breath. Besides, having robbed the atmosphere of 

 a portion of its vital part, we also set free at the same 

 time its nitrogen, which forms four-fifths of its bulk, and 

 which is a gas that will not support life. On an average, 

 about twenty pints of air thus vitiated is expired in each 

 minute from the lungs. Exhalations are also continually 

 passing from the skin of the human body, and to an 

 extent far greater than is generally known. Taking 

 these well-ascertained facts into consideration, it is a 

 matter of no surprise that the air of an ordinary-sized 

 room becomes "close" and unpleasant, when even only 

 a few persons may bo living in it. Careful chemical testa 

 discover the fact, that our bedrooms invariably contain a 

 larger amount of carbonic acid in the morning than on our 

 retiring to rest ; and if three or four per cent, of this gas 

 exists in the air of a room, it is sure to prove harmful, 

 not to say dangerous, to the inhabitants. 



Another cause of the vitiated state of the air in con- 

 fined apartments, is the combustion of various articles 

 employed for the purpose of giving light. Coal gas, 

 animal and vegetable oils, parafin, and tallow, are all 

 composed of the same substances, united in different 

 proportions namely, hydrogen and charcoal. These, 

 with oxygen, produce, during combustion, carbonic acid 

 and water. It must also be kept in mind, that a minute 

 portipn of coal gas, and some of the more volatile 

 parts of oils, always escape unburnt, and hence increase 

 the vitiation of the air beyond that produced by their 

 complete combustion. The annexed table we have calcu- 

 lated from data supplied by Dr. Frankland ; and it shows 

 the amount of carbonic acid produced per hour, by 

 quantities of each material sufficient to produce a light 

 equal to that of two sperm candles of six to the pound. 

 Tallow candles .... 3.00 cubic foot. 



Wax , 83 



Sperm oil 64 ,, 



Coal gas (London) . . . .60 ,, 

 From which it appears tliat tallow candles give off one 

 cubic foot per hour of carbonic acid gas, and ordinary 

 coal gas half a cubic foot per hour, when these are em- 

 ployed to light a room to only a very moderate extent 

 in fact, affording a light but little better than that pro- 

 duced by burning two "composite" candles. As, how- 

 ever, when gas is used, a much greater light is always 

 maintained, the production of carbonic acid may be 

 reckoned as equal to four times that indicated in the 

 above table, when two burners of the ordinary size are 

 employed in our sitting-rooms. 



VOL. I. 



The products of gas combustion are not only prejudicial 

 to animal life, but are also injurious to furniture, books, 

 die., on account of the production of sulphuric acid, or 

 oil of vitriol, by the sulphur in the gas uniting with the 

 oxygen of the air. The effect of this acid is found in the 

 complete destruction of the leather of bound books, and 

 of most animal and vegetable substances with which it 

 comes in contact. The colour of many articles, such as 

 curtains and window blinds, is also injured by it ; and 

 hence an absence of ventilation is at once a source of both 

 disease and expense. 



Our remarks have been confined to instances where a 

 want of good ventilation can be chiefly ascribed to the 

 ignorance, and not the want of means of those who suffer 

 from it. When, however, we descend in the social scale, 

 it is scarcely possible to exaggerate the physical and even 

 moral evils which result from inhaling and living in an 

 atmosphere of foul air. Those who have made it their 

 business to visit the houses of the majority of our work- 

 ing classes, have no difficulty in discovering the causes 

 which produce fevers of the typhoid class, and the conse- 

 quent fearful mortality wliich ensues. It is by no means 

 an uncommon case to find four or six persons cooking, 

 eating, and sleeping in one room, of very contracted 

 size, from which foul air can scarcely escape, and into 

 which pure air rarely flows, except in the smallest quan- 

 tity. For the purpose of economising fuel, these apart- 

 ments are always kept closely shut up. In towns where 

 gas is generally hud on even to the poorest houses, such 

 as Glasgow, Edinburgh, etc., the room is often kept 

 warm by the gaslight, and another source of impurity is 

 thus continually in active operation. The expenditure 

 incurred, and the time necessarily employed in washing, 

 is often a barrier to cleanliness, especially in manufactur- 

 ing districts, where every member of the family is ordi- 

 narily engaged at the factory. Disease of the lungs, 

 phthisis, <tc. , are natural results of the sudden changes of 

 temperature which are undergone by persons thus living 

 in confined apartments, who are necessarily exposed to 

 the cool air, as they pass to and from the place of their 

 daily avocations. In a moral point of view, the results 

 are equally lamentable. Want of pure air, and a con- 

 tinual breathing of impure air, induce a languor of the 

 system, which in most cases is relieved by spirituous 

 drink. Add to this the contrast of the liandsomcly 

 fitted and often well-ventilated public-house to the hovel 

 the man has escaped from, and we at once find a solution 

 of the social enigma of drunkenness, poverty, and desti- 

 tution. 



Having stated some of the causes which tend to render 

 the air of an apartment impure, we proceed to consider 

 some of the different plans wliich may be adopted, or 

 have been proposed, for the purpose of remedying the 

 evil. 



The simplest mode of ventilating a sitting or bedroom is 

 that of leaving a space between the bottom of the door 

 and the doorway, for the admission of fresli air, and of 

 having an opening at the top of a room communicating 

 with the outside of the house, by which the foul air may 

 escape. The latter may easily be effected by the removal 

 of a brick, and by covering the opening by means of an 

 iron grid, or a piece of perforated zinc. A still better 

 ol.iu is that of having a large opening in the centre of the 

 ceiling, communicating with the open air. This may be 

 concealed by means of an ornament of any kind. Many 

 objections have been made to admitting air at the lower 

 part of a room, owing to the strong draughts which are 

 thus produced. A very ingenious arrangement has lately 

 been patented, *hose principle will easily be understood 

 on trying the following experiment : 



Experiment 30. Place a glass bell-jar, as represented 

 in Fig. 14, at (a), so that its lower end may rest evenly on 

 any flat surface, and thus prevent any air entering. In- 

 troduce a lighted candle into it, and, after a short time, 

 the candle will be extinguished for want of air, although 

 the top of the jar (6) may be open. Relight and replace 

 the candle, but now divide the neck of the glass jar by 

 inserting into it a card (c) so as to form two sections or 

 openings. It will now be found that a current of air 



I 



