ing; each joint is an element of weakness, and the system of hanging tubes is disapproved by many engineers.

Jan. 8, 1874. Mr. Samuel Batchelder, of Cambridge, presented a dynamometer of his invention, with a detailed description of the same. It is applicable both to steam and water power, for heavy or light machinery, and affords the means for accurate measure of power exerted.

Prof. Whitaker then read a paper on shafting as a means of distributing power, alluding to some of the old-fashioned methods of shafting mills, some deviations from these methods in use, and others contemplated. Without wishing to condemn the prevalent use of light, rapidly-rotating shafting, he stated, that, though this appears to consume much less power than heavier shafting, the difference is far less than is generally believed; the gain, he thought, was more in the use of better materials, more careful workmanship, and more perfect lubrication, than in the increased speed of the lighter shafting.

Jan. 22. Mr. Albert K. Mansfield, of Lowell, made a communication on the "Theory of Turbines," passing in review the four principal methods of converting the power of water in motion into useful effects, viz.: 1, by impact; or allowing the water to impinge on planes, or floats in motion, set at right angles, or nearly so, to the direction of the flow; 2, by pressure; the water pressing on the floats in motion, but so confined as to move no faster than these; 3, by reaction; of the water flowing from orifices against their walls; 4, by deviation; of the water from the direction in which it tends to flow, according to the principle that a body resists deviation from straight line motion. The action of water in wheels is often a combination of two or more of these methods. He gave the theoretical formulæ in each of these cases.

Prof. Whitaker drew attention to the indefinite way in which the word theory is used, as distinguished from practice. The popular, and a very mischievous, belief is that practice is opposed to theory; practice may be opposed to hypothesis, which many mistake for theory. Theory, in its true sense, means the

whole theory of a scientific problem, all disturbing elements having been considered, and thus is the same as practice. When an incomplete theory is under discussion, its incompleteness should be stated, and then we should hear no more of the supposed, but really non-existent, antagonism between theory and practice.

Feb. 12. Mr. David Renshaw described from a model a new form of sectional boiler, of his invention, which had been in successful operation for several months in Hingham, Mass.

The material is cast iron, and the form that of the reverberatory furnace. This form secures the hottest part in the crown or arch, and by a gradual increase from below upward; the boiler is of a corresponding form, being in its outer portion a true half circle, giving the reverberatory form of furnace and drop flues; all the fire surfaces are directly over the grate, and are very large. The circulation is rapid, and cleaning easy; none of the joints, always a fruitful source of trouble in sectional boilers, come in contact with the direct action of the fire; they are very few, and very accessible. His plan retains the colder, heavier water in the lower portion of the boiler, where it ought to be a great security against explosion from sudden rise of pressure.

Feb. 26. Mr. Horace McMurtrie read a paper on "Boiler Explosions no Mystery" — being a careful review of the facts presented in the Report of the "Hartford Steam Boiler Insurance Company."

He alluded to the well known causes, of defective materials, faulty construction and form, and especially the ignorance and carelessness of those having charge of boilers. Improper riveting and insufficient bracing, safety valves overweighted or corroded in their seats, inaccurate steam and water gauges, defective setting, inattention to the supply of water, neglect of inspection, were in turn taken up. He gave the record of nearly 12,000 defects discovered in a single year by the inspectors, from the examination of a very small proportion of the boilers in the United States, and of these nearly 2900 were dangerous.

He thought the mystery was that, under the circumstances, more boilers did not explode.

March 12. Mr. J. R. Robinson read a paper, in answer to Mr. McMurtrie, admitting the facts stated, but citing numerous cases which had come under his official investigation, where the explosion of boilers could not be accounted for by any of the conditions above named. He believed that there was a mystery in the causes of these explosions, and that the only safe way was to investigate this mystery, so important for the users of steam.

March 26. Mr. Stephen M. Allen read a paper on "Light and Heat, and their relation to Steam."

Mr. Guthrie made a communication on the Morton Ejector Condenser, explaining its construction by diagrams. This condenser dispenses with the air pump; the exhaust steam escaping from the cylinder is so directed as to unite in a jet with the injection condensing water, by which it is condensed having first, however, imparted a sufficient velocity to the combined jet, to enable this to issue direct into the atmosphere in a continuous impulsive stream; the contents of the condenser, both water and air, are thus ejected without the use of the pump, and without impairing the vacuum maintained in the condenser.

An interesting discussion took place on various points suggested by this communication.

April 9. Prof. A. Graham Bell occupied the evening in remarks on "Visible Speech," or the "Science of Universal Alphabetics," a system invented in 1864 by his father, Prof. A. Melville Bell.

In this system sounds are represented by symbols indicating the positions of the vocal organs assumed during their production. These may be arranged in a linear series, like letters, forming an alphabet capable of representing the sounds of all languages-a system of universal alphabetics.

He illustrated its application in teaching the deaf to speak. In the deaf the vocal organs are perfect, and the deaf have

!

hitherto been dumb simply because they cannot hear and imitate sounds, and because the concealed mechanism of speech cannot be seen. By his system the deaf can see how to place the tongue, lips, etc., for the production of every sound, and thus to speak. The system was first introduced in England in 1869, and in America, in Boston, in 1871; it has been attended with remarkable success, and is now extensively used in this country for the education of the deaf and dumb, a class fortunately now not neccessarily dumb because they are deaf. Its value was demonstrated to the audience by several pupils of his. The system is now adopted by the Boston University. May 14. Mr. A. C. Cary, of Malden, made a communication on a process, invented by himself, of weaving on a rotary loom. It both knits and weaves at the same time, making a very strong, non-elastic cloth, of any desired width, a yard a minute, and at a very cheap rate. Specimens of this fabric were exhibited.

Mr. E. H. Hewins then read a paper on some of the principal points of difference between the American and European systems of iron bridge building, in which he gave his reasons for preferring the former.

May 28. Mr. Robert B. Forbes read a communication on the best means for preventing collisions at sea, and of strenghtening vessels.

The importance of the so-called Maury lanes, now adopted by the Cunard Company, was dwelt upon. The necessity of the adoption of some such plan has been demonstrated by a series of recent terrible disasters.

He advocated the frequent use of the steam whistle in a fog, sounded so as to indicate the general course of the ship. He dwelt also on the necessity of having ships with double bottoms, without openings between engine room and fire room, or between coal holds and fire room, except in the last by some sort of elevator to carry the coal over the load line into the receiver, near the furnaces.

Mr. C. W. Hinman, a graduate of the Institute, and now "State Inspector of Gas," made a communication on "Gas Analysis."

After giving a 'history of the apparatus and processes employed by Lavoisier, Bunsen, Regnault, Williamson, and Russell, he explained his own in detail. His process is much simpler than any others in use.

Mr. C. A. Morey, a pupil of the Institute, described the various methods of rendering sounds visible, and gave the results of an extensive series of experiments made by him the past winter with the "Phonautograph" - modified and improved by himself. The curves made by the style set in motion by the vibrations of the membrane of the instrument, were exhibited, highly magnified, by the oxy-hydrogen lamp.

There have been elected during the year eight associate members. Seven associate members have died during the year viz: Messrs. Copeland, Derby, F. H. Jackson, Jewett, Reed, Sweetser, and Thompson; five have resigned, and fourteen have been dropped for non-payment of fees. The list now comprises 297 members.

The attendance at the School of Industrial Science for the year, has been 310; as follows: Resident Graduates, 2; Regular Students of 4th year, 21; of 3d, 34; of 2d, 59; of 1st, 68: Students not Candidates for a Degree and Special Students; 4th year, 13; 3d, 27; 2d, 25; 1st, 35; Students in Practical Design, 26, of whom 15 were females. Of these, as in former years, nearly five-sixths are from Massachusetts, principally from Boston and vicinity; from other New England States, 17; viz: from Maine, 5; New Hampshire, 5; Vermont, 3; Rhode Island, 3; Connecticut 1. From other States there are from New York, 7; Ohio, 8; Pennsylvania and Illinois, each 5; Minnesota and Western Islands, each 3; Indiana, Kentucky and California, each 2; New Jersey, Maryland, Kansas, Missouri, Nebraska, Colorado, British Provinces, Japan, and the Sandwich Islands, one each.

Thirty-eight professors and teachers have been connected