SURFACE CONDENSERS. 105 
ratio for these condensers, and this works out to be 2,030. I have not been able to find 
enough data to permit that ratio to be worked out for the Cantigny, but taking the 
results given for surface, water, and speed, the ratio works out to about 2,030. If we 
could have the additional information for determining this coefficient, it would be of 
value. 
I believe the condenser for the Cantigny is rather conservative, because there is no 
reason why the speed of the water through the tubes should not be as high as 6 feet per 
second. I think that in most of the condensers that have been designed in shipyards 
during the last few years the speed of water through the tubes has been more nearly 
one foot per second, and a great deal of unnecessary surface has been placed in the con- 
densers for this reason alone. 
I would also like to point out that in condenser design you do not gain very much 
by trying to play safe. Practically all surface which is added to the condenser, after 
you have enough to condense the steam, is added at the bottom of the condenser and is 
effective only for cooling down the air or for chilling the condensate. If you get the 
temperature record for water while passing through a condenser, you will find that where 
the water passes in at the bottom and out at the top there is a very slight increase in 
temperature during the first pass, if the condenser is over-surfaced, and a very rapid 
rise in temperature during the second pass through the steam at the top. When you 
play safe by putting in a lot of surface, all you are doing is to cool down the condensate 
and make the temperature of the hot well lower. 
I would like to ask what quantity 17 is on Plate 46, ‘‘heat per pound steam.’’ I find 
from the steam tables that when the condenser pressure is 1.14, the total heat is about 
1,106 British thermal units. The heat of the liquid at 83.2° is about 51, giving 1,055 
British thermal units, and I am wondering how the 988 British thermal units are ob- 
tained. 
Mr. Harotp F. Norton, Member:—Professor Bragg in his remarks yesterday 
appeared to indicate such a lack of familiarity with the production of lines in the case 
of new designs in the shipyards that it seemed scarcely necessary to make any reply, 
but, as he has mentioned it again today, perhaps it might be well to say that when lines 
are to be got out in a shipyard we do not merely pick out some draughtsman and say 
“‘Please get out this set of lines for this new ship.”” We have, at all the principal yards, 
I am sure, men who are particularly familiar with that work, and whose particular 
business it is to get out lines for a new ship. We would like to assure Professor Bragg 
that these men have access to the transactions of this Society, and the transactions of 
every other society, and we would also like to assure the members of the Society that 
we take advantage of all such papers, before getting out the lines of a new ship, and that 
these papers are greatly appreciated. 
The above is intended as an appreciation of the work of the Society and to indicate 
what might be said to the professor’s remarks, rather than any idea that so distinguished 
a member of the Society and the profession is unfamiliar with shipyard practice in pro- 
ducing the lines of a new vessel. 
Mr. Geo. A. Orrox, Member, and E. B. Ricketts, Visitor (Communicated) —The 
author gives some very interesting figures on heat transfer obtained in an experimental 
condensing outfit at the Engineering Experiment Station at Annapolis. The data, 
