"I think this discussion of the peculiar phenomena exhibited in steel is so very interesting that we ought to have some day a sort of symposium presented by the members of the Society on steel phenomena. Each member can contribute, what would amount perhaps to half a page, describing some peculiar phenomena which he has witnessed, bringing facts, not theories, that will add to the amount of our knowledge on steel and lead to some true or some better theory of these peculiar phenomena. I make that suggestion for the topical discussions for the next meeting."

The queries were as follows:

What experiences and phenomena can you describe as to the conduct of steels under the conditions in which you were using them?

How much allowance is wise in shrinkage fits with steel?

What is the best form of cross section to adopt for steel castings of a complicated nature, in order to secure solidity and freedom from shrinkage cracks? How often must the skin of steel be removed in grinding true gauges, etc., before change of form ceases?

The debate was participated in by Messrs. Hibbard, Fuller, Kent, Huston, Stetson, Dingee, Fawcett, Main, O. Smith, Hunt, Denton, Sweet, and Bond, by several of whom illustrative samples were exhibited: The debate was arrested before its conclusion in order to admit of a trip on the Suburban Electric cars.

FIFTH SESSION. THURSDAY EVENING, OCTOBER 18.

This was called to order at eight o'clock by Vice-President Henry G. Morris, who took the chair. The paper by L. H. Rutherford, of New York, was presented by F. R. Hutton, and was entitled "The Strains on an Annular Lid Resisting Internal, Pressure." It received no discussion. The paper by Mr. C. J. H. Woodbury, of Boston, was entitled, "Electric Welding," and was discussed by Messrs. Kent, Oberlin Smith, and Ralph I. Pope (by invitation).

The discussion of steel phenomena was again taken up, being participated in by Messrs. Hunt, Richards, Yost, Barr, Wheelock, Oberlin Smith, Crane, Whitehead and Hutton.

The query:

"What is the best method of preventing variation in pitch of screw-threads, as cut by dies in the screw-machine, resulting from irregular stretching or flow of the metal, caused by the action of the dies when operating upon large numbers of comparatively long screws of small diameter ?"

was discussed by Mr. Whitehead.

At the close of these discussions, the following resolutions were severally presented:

By Mr. B. H. Warren, seconded by Mr. Oberlin Smith:

Resolved, That the American Society of Mechanical Engineers desiring to express their high appreciation not only of the honor conferred upon them by the Board of Trade of the city of Scranton, in the official invitation sent them through their President, William Connell, Esq., and J. H. Fisher, Secretary, to hold their eighteenth meeting in this city, but as well for the attention and kind. ness shown them during their stay, hereby tender them our sincerest thanks and would as well express the hope that through the efforts of the Board of Trade supplemented by the labors of the Mechanical Engineers, the city of Scranton will continue to show in the future the same marvelous development that has marked its progress in the past.

By Mr. Robert Hunt, seconded by Mr. Durfee:

Resolved, That the American Society of Mechanical Engineers hereby expresses to the Entertainment Committee, through its chairman, Col. Boies, so ably assisted by the ladies, its cordial thanks for the opportunities so pleasantly offered for meeting the citizens and ladies of Scranton, and for the many other courtesies so warmly extended, and especially in their kind attentions to the ladies of the visiting members, and to tender congratulations to the committee and ladies, that they are enabled to extend those hospitalities in a city so charming in its location and beautiful surroundings, its well-known educational system and advantages, and its commercial honor and integrity.

By Mr. George H. Babcock, seconded by Mr. Weightman:

Resolved, That the hearty thanks of the ettending members and guests of this society are hereby expressed for the hospitality extended by the Erie and Wyoming Valley Railway and Delaware and Hudson Canal Company, by whose liberality, courteously administered in person by their respective superintendents, Mr. George B. Smith and S. A. McMullen, we have enjoyed a delightful excursion through one of the most picturesque regions of our country, and have experienced the pleasure and novelty of a ride over the famous Gravity Road of the anthracite coal fields.

By Prof. J. E. Sweet, seconded by Mr. J. T. Boyd:

Resolved, That the thanks of this meeting are hereby expressed to the Dickson Manufacturing Co., through its manager, Mr. J. P. Dickson; the Lackawanna Iron and Coal Co., through its manager, Mr. E. S. Moffat; the Pine Brook Colliery, through its manager, Mr. Brooks; the Boies Car Wheel Co., through its manager, Mr. Pearson; and the Scranton Packing Co., through its manager, Mr. Hendricks, for the courtesy extended it in opening their interesting works to inspection and for the cordial manner in which visitors were entertained.

Resolved, That the thanks of this society are hereby tendered to the Suburban Railway Company, through its courteous President, Col. Geo. Sanderson, for the privilege of inspecting the appliances and enjoying the use of their novel and progressive enterprise.

By Prof. J. E. Denton, seconded by Mr. Bond:

Resolved, That the members of this society hereby tender their thanks to Messrs. Dexter, Lambert & Co., of Hawley, for the opportunity so courteously offered for visiting their silk mills; also to Messrs. Christian Dorflinger & Sons for like courtesies during a visit to their glass works at White Mills, where they

enjoyed the privilege of witnessing the interesting and intricate operations of their respective industries.

By Mr. W. M. Barr, seconded by Mr. Suplee:

Resolved, That the society tender its thanks to Mr. W. W. Scranton for the invitation extended by him to visit the Scranton Steel Works, and say to him that while it has been impossible up to this time to avail ourselves of the same, that we hope to be able to do so before we leave the city.

By Acting-President Woodbury, seconded by Professor F. R. Hutton:

Resolved, That while all have done much to make our visit to Scranton one of pleasure as well as profit, we recognize the fact, that here as elsewhere, the burden falls on the local committee, and ere we turn our faces homeward, we would tender them and their attentive and efficient chairman, Mr. W. F. Mattes, our heartiest thanks for all the good things they have done for us.

After a few words of reply from Mr. Thomas Dixon, of the city of Scranton and the repetition of the announcement that the Spring Convention of 1889 would be held in the city of Erie, Pa., the meeting adjourned.

EXCURSIONS.

Tuesday afternoon was devoted to a visit to the works of the Lackawanna Iron and Steel Co., including both the iron furnaces and the steel plant.

In the evening a reception was tendered to the society and their ladies by the Board of Trade of Scranton. This was held in the parlors of the Y. M. C. A. building, with music and a collation.

Wednesday afternoon was devoted to visits to the shops of the Dickson Mfg. Co., the Boies Steel Car Wheel Works, and the Pine Brook Colliery. In the evening, after the adjournment of the professional session, the members took a trip over the line of the Suburban Electric Co., stopping at their power plant.

Thursday was devoted to the trip to Honesdale, stopping at Hawley and White Mills at the silk mills and glass works respectively. From Honesdale the party returned to Carbondale over the gravity lines of the D. & H. C. Co., and from thence back to Scranton.

Friday morning a visit was paid by the society to the Scranton Steel Works at the invitation of Mr. W. W. Scranton, its president, after which the members dispersed.

CCCXII.

THE STRAINS IN AN ANNULAR LID RESISTING INTERNAL PRESSURE.

BY L. H. RUTHERFORD, FRANKLIN, PA.
(Presented by F. R. Hutton.)

INTRODUCTION.

The occasion recently arose in the writer's practice to decide upon the strains in an annular casting, to which a flexible diaphragm was secured, when fluid pressure came normally upon the latter. A large cylindrical vessel, seventy-three inches in diameter, had to have a lid which could be easily opened, and should be light. It was therefore decided to make this lid of copper sheet of an inch thick, and to rivet this copper to a cast-iron ring, which would give the necessary stiffness to secure a steam-tight joint when bolted to the flange of the cylinder, and would allow of arranging a convenient hinge structure. The copper part was a segment of a sphere struck with a radius of fifty-seven inches, running into the tangent at 30°, as shown in the sketches, and was riveted by eighty-four copper rivets at 23" pitch. The diameter of the pitch circle of the rivets was 66 inches.

The section of the cast-iron ring is shown in Fig. 3, where it will be observed that the lid was held to the flange by 16 bolts, 2′′ in diameter, and the tightness of the joint against leakage was secured by a ring of sheet rubber 1" x 11", let into a groove. The vessel had to withstand an internal pressure from steam of 65 lbs. to the square inch, tending to blow out the copper and flex the cast-iron ring to which it was riveted. It was early found in the investigation that the strain in the ring could not be evaluated by the simple arithmetical methods which are usual and preferable, since they could not be made to embrace the intricate relations of the stresses. The interest of such a case to designers generally, and the advantage which it may prove to others to be able to refer to such an analytical investigation, have induced me to request Mr. Rutherford, by whom it was undertaken, to consent to its publication inthe Society's Transactions. F. R. HUTTON.