necessary really for the make-up of a thorough-going man." We confess to a lively sympathy with the horror felt by the heating and ventilating engineers in his audience until Mr. Taft relieved their suspense by the qualifying statement, "That, doubtless, is not true and I withdraw the remark if it is to be construed in a serious way. Perhaps, however, now the campaign is over, it will not be quoted against me!" As a matter of fact the mechanical plant in this particular institution, including the heating and ventilating arrangements, are, we understand, in keeping with the most approved modern practice and beneath the irony of the President-elect's comments was really a high and deserved compliment of the striking improvements shown in the construction of this particular type of building.

OME curious results of experi

ments to ascertain the amount of carbonic acid gas in the air in certain parts of England, as well as the amount of carbonic acid gas given off by different persons under different conditions, were described recently by Mr. W. Thomson speaking before an English society of sanitary engineers and reported in the Compressed Air Magazine. Using the method of forcing air into a bottle with an ordinary pair of bellows and submitting it to a simple chemical test, the results of his experiments showed that the amount of carbon dioxide which a man breathed out depended upon the quality of the air by which he was surrounded. In Manchester he breathed about 4% and in the country 5%, so that it would appear to be necessary to take about one-fourth more food in the country

than was sufficient in town. The breaths of three men were tested. In Manchester the percentage of carbonic acid gas given off by each was —A 4, B 3.8, and C 4. At the Buxton golf links, 1,000 feet above sea level, the figures were 5, 5.2, and 5.2, and after they had played eighteen holes and had lunch they each gave 4.8%. They then drove to the Cat and Fiddle, 1,700 feet above the sea, and there A gave 5.2, B 5.4, and C 5.4. These results suggested that the amount of carbonic acid gas exhaled was influenced by altitude. But a test made at Blackpool did not sustain the theory.

He found, too, that when the air was inhaled through the mouth the breath was about 0.2% lower in carbon dioxide than when the nostrils alone were used. This was suggested to him that if the air were artificially heated a still greater oxidization would take place in the body. Air heated to 140° centigrade was breathed, and the exhalation contained 5.4% of carbon dioxide, whereas exhalation of ordinary unheated air from the same person gave 4.4. The average in a number of experiments gave 4.1 from ordinary air and 5.1 from heated air. When pure oxygen was breathed the exhaled air gave an average of from 4.4 to 4.5, which was considerably below what one got from breathing in the country. It would appear, therefore, that country air was better for reviving people who had been asphyxiated or nearly drowned than pure oxygen, and that a maximum effect would be obtained from warmed country air and oxygen combined. It was found, however, that the hot air breathed in a Turkish bath had not the same effect as hot air breathed when the body was only at its normal heat.

While much has been accomplished in the field of electric heating as applied to lighting, metal welding and forging, and to electric furnaces for various industrial operations, the application of electricity for low-temperature heating, generally diffused and in large volumes, suitable for house-warming purposes, has left wide gaps to be filled. It is interesting, therefore, to notice in a recent discussion of the general subject of electric heating, presented November 13, 1908, before the American Institute of Electrical Engineers, by W. S. Hadaway, Jr., that the speaker took occasion to review what had been accomplished, as well as the lines upon which further progress should be made, in the application of electricity on a commercial scale to the warming of buildings. The main features of Mr. Hadaway's paper concerning this side of his subject are contained in the following ab

stract:

It may assist in a better understanding of the terms used in discussing electric heating to state at the outset that the words heat potential, etc., are employed more specifically than has generally been found necessary in discussing heat effects apart from electricity. Heat, like electricity, is assumed to flow from a surface of high potential to one of low potential. Quantity or volume of heat is analogous to quantity of electricity. Unit quantity is here figured as the British thermal unit, though for electrical purposes it is, of course, the calorie. Temperature corresponds to potential. Heat potential is as true an expression of potential as is impressed electromotive force; it should not, however, be comfounded with static potential, a term used in discussing energy of gas. It would materially simplify thermal nomenclature if a word were coined to designate heat potential in the same manner that electromotive force expresses electrical potential.

The term "electric heating" is commonly used to express the filtering down of the higher potential energy of electricity into the lower potential energy of heat. There is no well defined line of demarcation; the result is inseparable from the conveyance of utilization of electricity in any degree. The expression is, therefore, a meaningless one from the heat engineer's standpoint and it fails accurately to express the performance of useful work by the transmission of heat energy to a distance by means of electricity. The expression, "electricity, a factor in a telethermic system," would be a better definition, but for obvious reasons the shorter and simpler expression is employed.

Heat energy is to be regarded as a commodity that can be generated or controlled in convenient form and distributed and sold, and in which electricity is used either directly as the high-potential heat factor or indirectly as agent.

The feature of the subject we are to consider is the practical adaptability of commercial electricity for heating purposes and for performing useful work under the conditions imposed in general industrial and domestic life, and particularly in connection with other heat distributors for a multipotential heat supply.

TWO CLASSES FOR APPLYING ELECTRICITY FOR HEATING PURPOSES

These applications may be roughly divided into two classes according to the degree of concentration of the heat energy used. The first class includes low-temperature heating, generally diffused and in large volumes; the second includes high-temperature heating, generally localized and in small quantity.

In heating on a small scale no adequate classification is possible; it is the blending of high-potential heat energy into low potential-heat work for many useful operations that primarily suggests the feasibility of heat

transmission by electricity. An arbitrary line of temperature demarcation for heating on a large scale has been drawn at 250° F.

The closest common analogy to the differences between low-potential, large-volume and high-potential, small-volume heating is the distinction between volume and pitch in sound. As examples of the first class may be cited the heating of rooms and of water at atmospheric pressure; examples of the second class are electric ovens, sadirons, and soldering-irons.

The electrical unit or kilowatt

hour is the equivalent of 3412 B. T. U. For practical purposes the

work in hand is to determine the useful work in different lines obtainable from this number of heat units at a fair average cost of supply. There is involved indirectly the determination of relative efficiency between electric and other methods of heat generation, distribution, and application.

Figures tabulated farther on will show results obtained in water heating by various methods of heat application. The heat capacity of the work performed is sufficiently large to express the relative differences in combined efficiency, and, as we should expect, the lower the temperature of the work the larger the area heated; and the greater the capacity the less the difference in ratio between heating by combustion and by electricity. We may readily determine the conditions where the ratio is an inverse one.

CALCULATIONS FOR ROOM HEATING

In room-heating apparatus on continuous run we may estimate that one watt-hour, 3.41 thermal units, will heat I sq. ft. of common radiator surface through 1.26° F. that 1000 watt-hours or 3410 thermal units will heat the surface approximately 126° F. above the room temperature; that is, for room heating, from 85 to 110 watt-hours are practically the equivalent of steam at low pressure condensed by 1 sq. ft. of radiator surface with the difference between the room

and the radiator temperatures as above stated. This, of course, takes no account of the heat capacity of the apparatus, which is practically eliminated by the imposed conditions of continuous running.

We may safely assume that a fair average price of the electrical unit from large steam electric stations is 6.7 cents. It would therefore cost 0.65 cents average to run 1 sq. ft. of direct radiation surface for one hour, or the electrical unit would keep about 10.3 sq. ft. of radiator surface at the temperature difference noted for one hour.

COMPARISON WITH STEAM HEATING

Direct comparison of this value. with practical steam heating is difficult, owing to the variables involved. We may, however, compare it with a central station steam distributor as quoted by Unwin in his work on the "Development and Transmission of Power," referring to a New York steam company.

As

The unit of heat used by this company is defined as the "kal", which is stated to be the heat required to evaporate one pound of water from 100° F. at 361° F. or at 85 lbs. pressure per square inch. One kal is therefore about 1.110 thermal units. On a sliding scale the charge is stated to be 70c. per 1000 kals to small users and 40c. per 1000 to large users. the price of 6.7c. per electrical unit is to a fairly large user, we shall compare it with the 40c. per 1000 kal rate. For 40c. the consumer obtains 1,110,000 thermal units from the steam station, composed with 20,400 thermal units from the electric station, a ratio of nearly 54 to I, or practically 50 to I as a loss must be figured in the case of steam, dependent upon the temperature at which the condensed water is allowed to escape.

It is interesting to note in passing that while the relative efficiencies of generations are about as 12 to 1, the commercial rates quoted are as 50 to I. The ratio of the cost of heat energy from the electric station to the cost from the steam sta

of year. In all cities except Boston a continuation of last month's drought was experienced.

NEW YORK

Highest temperature, 84°, on the 17th; lowest temperature, 38°, on the 31st. Greatest daily range, 25, on the 15th; least daily range, 5, on the 27th. Mean temperature for the month, 60°, 4° above the mean of this month for 38 years. Total rainfall, 1.92 in., about 11⁄2 in. less than usual. Prevailing direction of wind, northeast; total movement, 8,470 miles; average hourly velocity, 11.4 miles; maximum velocity (for five minutes), 50 miles per hour from the northwest on the 30th. There were 14 clear days, 6 partly cloudy and II cloudy. Rain fell on 9 days.

PITTSBURG

Highest temperature. 80°, on the 16th; lowest, 34°, on the 3d. Greatest daily range, 39°, on the 4th; least daily range,

CR

YORK FOR OCTOBER, 1908

1908