underground, but often lodged in miserable and unventilated and over-crowded places, in the lodginghouses in which he finds quarters during the night,— or, in fine, that of the great masses of the labouring poor, at least of those living in the towns, who are crowded into rooms that are unaired, and little if at all visited by sunshine, not to speak of their being surrounded by other sources of impurity and disease, —and can we wonder at exhaustion and pallor, or even blame unpityingly, or without much qualification, the sad abuse of stimulants, which so aggravates eventually all the other evils, can we wonder at visitations of epidemic disease, at the greater number of cases of severe sporadic disease,-can we wonder at the much shortened life, at the accessions to the numbers of the widows and the orphans, at over-burdened pauper-lists, or at any amount of destitution or immorality? Too much cannot be said or thought about the effect of ventilation, in increasing the expectation of life, in raising the value and character of existence, in improving the physical condition, and with it to some necessary extent, the moral character, of the masses of a city-population. In many of the great factories, and in public hospitals, much has been done in this way,and too much praise cannot be bestowed upon those by whom the poor and the afflicted have been cared for in this essential particular; but the good may be carried farther, with much additional advantage, in the majority even of these more enlightened instances of philosophic endeavour; and it must be extended

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to the smaller workshop and workroom, to the poor man's dwelling and his dormitory, if all the good is to be derived from an acquaintance with the usefulness of a full and free ventilation, that we are entitled to expect from it. The amount of good from what has been done, is large beyond any preconception that could have been entertained;-the diminished mortality of the sick in the hospitals, the improved health, and greater aptitude and quickness at their work, of the operatives in the factories,-have been the rapid and extensive consequences of every step in advance that has been taken in this matter. And it should be borne in mind by all who draw together numbers of people into large buildings,-whether from a philanthropic wish to cure their ailments,-or from a selfish wish to support paupers at the cheapest rate, or from the mercenary wish, using the expression in no invidious sense, to increase their own commercial gains,-that it is their bare duty to provide that this is not followed by any injurious consequences to those, who are the creatures of their benevolence, or the tools of their aggrandisement ;— that there is ever much risk of injury to individual health, by collecting large numbers of people into the same building, for any lengthened period of time; and that this risk is only to be prevented, by adopting the fullest means of satisfactory ventilation, to carry off the concentrated animal miasms which are so detrimental to health and to life, whether acting insidiously and gradually, producing cachexia with all its consequent morbid

states, or rapidly engendering endemic or epidemic disease.

The calculations, as to what is to be considered an adequate supply of fresh air for every individual occupying an apartment, have varied a good deal. The comparatively low estimate of Mr. Tredgold, states that there should be 4 cubic feet of fresh air per minute, for each individual; whereas Dr. Reid seems to think that not less than 10 cubic feet per minute is only an adequate supply for every person. "In a room," says Dr. Reid, "12 feet square and 12 feet high, containing, therefore, 1728 cubic feet of air, there are ten persons who respire the whole air in the room in 15 hours, and require a complete change every 17 minutes in order to supply them with 10 cubic feet per minute. Such a change might be effected by the ingress and egress of air through apertures, 1 square foot in area, at the rate of 100 feet per minute, or 1 mile per hour. In the same manner, in a church, 80 feet long, 50 feet wide, and 40 feet high, containing therefore 160,000 cubic feet, there may be 1000 persons. For their supply there would be required a change every 16 minutes, or about 20 tons of fresh air every hour."* Inhabited rooms should then either be large and lofty, in order to contain such a number of cubic feet of air, in proportion to the number of its occupants, as will secure the maintenance of the atmosphere in a state of adequate purity, by means

* Dr. Reid's "Illustrations of the Theory and Practice of Ventilation."

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of a gentle current of air passing in and out of the apartment; or if the rooms are smaller, or the number of occupants greater, the currents of air in and out of the room must be more rapid, or the ventilation must be defective, and the condition of body and mind must suffer in the same proportion. The quotation from Dr. Reid furnishes numerical data, that are probably sufficient guides as far as figures can be so; the truth being, however, that, in the first instance, the sensations of a person unaccustomed to respire a vitiated atmosphere,—and, in the second place, the physical condition of the miserable and habitual victims to the use of an impure air, afford indications that cannot be mistaken. It is probable that none of the public places, in which the people of this country are collected together in considerable numbers, the larger and loftier churches alone excepted, have an internal area that is sufficient for the respiratory uses of the numbers of persons assembled, without so rapid a current of air through them, as to form a serious inconvenience, if not to become in itself a direct source of evil, to those who are within the influence of such currents. These remarks apply to theatres, ball-rooms, courts of law, public dining-rooms, and other familiar instances of much frequented or crowded public places; and the headache, and the general sense of lassitude, so commonly experienced, especially by the more feeble, and those particularly in whom the respiratory function is performed less vigorously and fully, and in whom the blood is

therefore most easily deteriorated beyond the physical sufferance of the economy, are the familiar examples of this fact. Such consequences are sufficiently undesirable, and, under some circumstances, may not be unattended with immediate or remote risk to health, or even life; as, when many days or nights are passed in an atmosphere so vitiated in its character, or when the general powers of the system are enfeebled, or when the respiratory organs in particular are disordered, or prone to become so; or, in another way, by the heat of so many living furnaces being so inefficiently carried off,-the pulmonary exhalations, and those from the skin, increasing the humidity of the air, and by the consequent risk of a sudden and great chilling of the system on re-exposure to the external air,-the nervous and vascular powers being in an unfit state to restore promptly the equilibrium of the circulation, from the depression and exhaustion that attend the imperfect oxygenation of the blood. Such evils as these are so evident and so easily obviated, that it is wonderful to find how little they are considered in providing accommodation for large assemblies, even of the wealthy and intelligent classes of the community. The architect is indeed unworthy of public confidence, and unfitted for the execution of his commonest duty, to whom the area necessary for the respiration of any required number of people, and the minimum current of air to be maintained through it for the respiratory wants of its occupants, are not primary considerations and familiar ideas. The