end of tubes.

Engine Building Company, the builders of the boilers of the "City of Trenton," asking for data referring to certain details of construction for a section of plate taken from the exploded boiler, for the purpose of making tests of same, and for information concerning the location of the exploded boiler on the boat, and the steam and water connections thereto.

To these inquiries an answer was received, the Counsel for the Company, J. Warren Coulston, Esq., saying in substance that, in his opinion, the present was an inopportune time to investigate the subject.

The chairman, therefore, stated that, in his judgment, the proposed discussion at this meeting would simply amount to an exchange of individual opinion among the members of the Section on the subject in its general bearings for the purpose of eliciting information respecting the construction and inspection of steam boilers, which would not represent the opinion of the Franklin Institute, and asked the meeting whether there was any objection to proceeding. No objection being offered, the chairman requested Mr. Vauclain to open the discussion. -THE SECRETARY.]

MR. VAUCLAIN:-Shortly after the explosion of the boat, through the courtesy of Mr. J. Shields Wilson and Mr. Sommers N. Smith (Mr. Wilson, I believe, operated the boat and Mr. Smith built the boat and also the boiler), I was permitted to view the exploded boiler on the wharf. This was a few days after the boiler had been taken out of the river. It required but a glance at the condition of the crownsheet to explain why the crown-sheet had blown down and the boiler had caused the damage that happened on that eventful day. The holes in the crown-sheet through which the crown-stays had been screwed were elongated, and were also enlarged in their upper diameter; or, in other words, in the diameter not next the fire but next the water -which indicated that as the sheet being hot, these holes had gradually enlarged in the upper diameter until the rivet-head of the stay could no longer hold it in position.

I have with me three photographs which were taken of

the boiler as it rested on the wharf. A glance at the point there of these two would, I think, enable any one who has ever had any experience with locomotive boilers at once to understand-I find the Secretary has slides of these three and will show them on the screen.

The crown-sheet is in this section and was the part that first became overheated; and the condition of the holes are as you will notice: there is one which shows very plainly (the direction in which the light comes through the holes rather spoils the picture); but in this one you will notice how the sheet is drawn, drawing the holes in an oblong shape. There were a number of these holes that were so drawn, and all in this vicinity.

FIG. 1.

The picture now shown is a view showing the interior looking into the roof of the boiler, showing where the fluesheet tore away and passed out with the crown-sheet. The crown-sheet is here, and shows very plainly the distortion, the holes being oblong and the sheet showing a corrugated appearance-part of it between these crown-stay holes.

This one gives you, perhaps, a little better idea of it. The light strikes it in a somewhat different manner. The light shadow on this print does not indicate the hole. Of course, a portion of the hole is shown in the very dark shadow. You will notice that the direction in which the photograph is taken shows the edge of the plate in the hole, as well as what light will pass through the hole; but

it brings out very clearly the distortion of the hole found

in the sheet.

The starboard boiler, however, was in position in the boat, and afforded an opportunity for an expert to learn exactly how the boiler was operated whilst it was in service; and this is what was found (Fig. 1): The boiler, having the ordinary fire-box of a locomotive boiler, and the crown-sheet stayed and held in a similar manner to locomotive boilers, with the flues extending from the flue-sheet in the fire-box to the flue-sheet in the smoke-box. The length of the firebox was about 9 feet 6 inches, but was shortened so as to give a grate-bar about 6 feet in length, as near as I could judge. Not having any drawings or accurate dimensions it is impossible for me to say what that length was; but at the end of these grate-bars a bridge-wall was built about 17 inches off the crown-sheet; consequently, all the products of

FIG. 2.

combustion (the wall being there) had to pass over this bridge-wall on the road to the flues, and consequently the flames were concentrated on this portion of the crown-sheet. It is therefore evident that when the water in the boiler got to too low a limit or down to the crown-sheet level, that the violence of the heat at this point overheated the crown-sheet; even if there had been a very little water over it, it would have driven that water away; and as the stays were constructed in this manner (being merely an eye-screw screwed through the crown-sheet and riveted there, Fig. 2), this portion of the metal would be the first to become heated, because on the upper side the water could not reach the plate. But I attach very little importance to this, as the time that would be required to heat this red-hot would be a little longer than what would be required to heat the plate surfaces, so very thin, after they were once exposed. The action when the plate commenced to get hot was with the stud being screwed in that way, and another one over here; there is a pocket in that manner (Fig. 3); and of course, when the plate would pocket in this manner on the other side of