NOTES ON RIVETS AND SPACING OF RIVETS FOR OIL-TIGHT WORK. 85 
tanker, makes a strong claim that it will be the most economical tanker afloat on account 
of being designed to carry but one kind of cargo. Tankers are so numerous now that it 
seems extravagant to design every one to carry mixed cargoes when this only happens 
occasionally. The probability is that mixed cargoes will be carried less frequently as the 
number of tankers increase. 
The time has already arrived when tankers should specialize on particular trades, 
thereby saving the expense of cleaning out the tanks, in which event the center-line bulk- 
head need not be absolutely bone dry. If, however, the necessity arises, at infrequent 
intervals, for carrying mixed cargoes, it should not be a difficult operation to avoid carry- 
ing a different kind of oil on each side of the center line in the same transverse compart- 
ment. 
Tue CHAIRMAN :—Gentlemen, I am sure you wish me to express the thanks of the 
Society to Mr. Frear for his fine paper and the discussion which the paper elicited, which 
I do. 
The secretary desires to make an announcement with reference to the excursion to 
the yard of the Federal Shipbuilding Company. 
THE SECRETARY :—Tickets for the excursion to the yard of the Federal Shipbuilding 
Company at Newark, New Jersey, can be obtained on application to the assistant secre- 
tary in Room 604 of this building. The steamer Pittsburgh, of the Pennsylvania 
Railroad Line, will leave the pier at the foot of Cortlandt Street, at nine o’clock sharp on 
Saturday morning, and luncheon will be served on the ship. The Federal Shipbuilding 
Company will have a reception committee with badges to show the visitors around the 
plant. 
THE CHAIRMAN :—The meeting will now stand adjourned until tomorrow morning. 
