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It would be certainly interesting to know the field of research whereby it was discovered that men at sea could under certain conditions apparently be, shall we say, content, with such a limited space. The usual method of deducting the air space required is of itself instruct- ive and interesting, namely: The amount of CO, given off by one person. Possible maximum quantity of CO, --CO, in 1,000°cu. ft. of air = Air re- quired per individual. The rules for computing the air space on board ship is laid down in the board of trade instructions to sur- veyors, and can be broadly stated as the most. that can be made of the floor space in square feet independ- ent of its utility, divided by 12, pro- viding always that the cubic capacity does not fall short. of 72 2cw.- ft. per seaman after deduction has been made for certain. encumbrances, such as hatches and ventilating trunks. For some reason, however, spaces occu- pied by bunks are not deducted. It is a noteworthy fact that buila- ers fit the maximum number of berths allowed by the board, independent of whether that number of crew are to be carried or not, and so greatly re- duce 'the all-too-small air space ac- cordingly. Perhaps it is to induce the owner to carry a larger crew, for we know that quite a number of owners realize that the Merchant Shipping Act complement of men is small, and for this great blessing, for it is a blessing, we who go down to the sea in ships are duly thankful. But why any berth should be a fixture, built in in such an immovable fashion, appa- rently on the same principle as the laws of the Medes and Persians, is a question perhaps the ship builder can best answer. Why cannot the great improvements effected ashore in this direction be adapted to ship re- quirements, and upon that basis I would suggest the following rules, in connection with ships' bunks, as a 'possible guide to health and cleanli- ness generally: Ist. All bunks should be construct- ed clear of the ships' side or bulk- head, to allow a free circulation of air. 2nd. They should be placed for preference against the inner bulk- head; that is, not against the ship side, 3rd. They should all be removable the framework of iron and _ wire springs substituted for the usual wood lathing. The sides or bunk boards TAE Marine REVIEW not more than 8 inches deep. The foot and head boards to be carried to within 6 inches from the deck above. The minimum dimensions being 6 ft. 6 in. long by 2 ft. 3 in. broad. The bunk to be as much above the deck as possible. The cubicle system of crew accom- modation, however, is preferable, pos- sessing more of the civilized ele- ment, and the class of men following the sea, who live forward, would un- doubtedly improve if the conditions of living were more pleasant. Stringent regulation should be en- forced regarding fitting lockers under bunkers or obstructing the free cir- culation of air by stowing boxes and the like under bunks in both cabin and forecastle. The farce of morning inspection of a ship by a commander ignorant of the elementary rules of sanitation, or a medical man who, with few excep- tions, is ignorant of the internal econ- omy of a modern vessel, generally re- sults in discomfort only, and is pro- ductive of very little good. The ordinary attempts at ventilation on board ship must, to use the mild- est language, be termed ill directed, possibly from a combination of want of thought and want of special knowledge. Conformity to the letter of the Mer- chant Shipping Act with regard to ventilation, irrespective of the ele- mentary principles governing the po- sition of ventilators, etc., in many cases is all that one finds, and venti- lators are more often so arranged as not only to be useless, but a source of annoyance when anything but the mildest 'weather is encountered. In some cases ventilators discharge di- rectly over a bunk. The natural con- sequence being it is kept plugged up from below to prevent intolerable drafts. This 'arrangement is more often than not due to the absurd no- tion of sacrificing all for appearance on deck, a condition which must give way to utility and practical science as it did under compulsion, when the black smoking funnel found a place on the before spotless deck to lay smuts belched forth with clouds of black smoke, and covering with soot, 'masts, riggings, and sails alike. Sir John Clarke, one of. the leading authorities on hygiene, says: "Air, as it increases in temperature, or be- comes loaded with watery vapors, has its weight diminished and _ ascends. Now the air in an inhabited apart- ment, being both heated and gener- ally combined with a portion of watery vapors from respiration, etc., 2/ becomes specifically lighter, at the same time that it is vitiated, and rises to the roof. If it is given the means of escape it would be gradually forced out by an equal quantity of pure and more dense air entering from below, which in turn becomes heated and deteriorated, would in like manner ascend and make its escape, thus would a continual current of the air circulate without any trouble on our part. Unless provision be made for the escape of the ascending current of impure air, no admission of exter- nal air will secure proper ventilation." This in compartments where the changes could be made withotit caus- ing a draft would be highly desira- ble. But where it is considered that under natural conditions, air cannot 'be changed more than three times per hour without creating a draft, to- gether with the following table (taken from a reliable source) of the rate of increase of impurities, it will be no- ticed, and I think forced home to any of my hearers who may have control of such things, 'that. air im oa Small Space becomes impure quicker than in a large. RATIO OF IMPURITIES FOUND IN AIR PER HOUR, 1,000 cu. ft. 500 cu. ft. Thourviae.: O12; per. (Cent ..005 0.18 per cent. 4°) outs. <3: 0.30 Aper-icent.y ss. 0.54 per cent. 6 hours..... 0.42 per cent. 6.5.5 0.78 per cent. One is apt to speculate after perus- ing the above. What would be in the figure for 72 cu. ft., under sea condi- tions where ventilation can generally be classified as non-existent? It is obvious, therefore, that for ves- sels trading in cold climates, some system of heating the in-coming air is necessary to enable sufficient air changes to be effected without undue draft, and adequate heating at that. ' Ventilation can be classed under two broad heads, natural and mechan- ical. Of the natural system for ma- rine purposes, the Boyle patent air pump system certainly ranks high. The essential features of this system are the air pump ventilator (uptake), consisting of an arrangement of metal plates, at certain curves and angles, enclosed in a central chamber, from which the air is exhausted through a series of openings or slots, by the deflecting of the current of external air across the opening, .and so cre- ating an induced current in the ven- tilator and up the shaft and a down current ventilator of such a form, that the heads require no trimming, and a series of air shafts completes the system. The makers claim for this system the following advantages: 1. Boyle's patent "air-pump" ven-