168 REFRIGERATION AND REFRIGERATOR INSULATION ON BOARD SHIP. 
with clear record that it is slow burning and will be a defense to a ship rather than an added 
hazard if she should have a fire in her holds, it will be impossible to introduce it widely. 
“There is one statement in Captain Lundin’s paper regarding the buoyancy of cork 
as compared with balsa wood that is undoubtedly a misprint, since it is an absolute mis- 
statement of facts. The statement is, that at the end of forty-nine days “the cork had lost 
its buoyancy.” The natural structure of cork is such that it will not lose its entire natural 
buoyancy in forty-nine years, to say nothing of forty-nine days. 
“Referring now to Professor Carpenter’s remarks, I note his statement that the heat 
transmission of balsa wood is .35 British thermal unit per degree Fahrenheit. This I take 
to be per degree Fahrenheit per hour, giving a heat transmission per 24 hours of 8.4 British 
thermal units, which is about the same as lith. 
“T have not seen the report of the Bureau of Standards, but I understood recently that 
they gave pure sheet cork a heat transmission of 7.4 British thermal units. This would be 
.309 British thermal unit per hour, which is less than Professor Carpenter states in his re- 
marks. 
“Captain Lundin intimates that the balsa wood will cost as much as pure cork sheets to 
install. Professor Carpenter’s remarks indicate that the insulating value is about 13% per 
cent less efficient than an even thickness of pure cork sheets. As to the claim of less joints 
in the construction there is nothing to that to any practical extent, since cork can be made 
of any size that the trade requires within reasonable limits; 7. e., they can be made from 
6 to 8 square feet to the board without any difficulty. Cork is now being made in Spain 
36 inches by 24 inches. 
“The only advantage the balsa wood may have is somewhat greater structural strength _ 
and in certain places this would be of real advantage, though, after all, such cases 
would be very limited in number, because it would not do to form an independent building 
wall; and as for partitions, we know perfectly well that pure cork board without any wood 
in the construction can be erected in partition form amply strong for dividing interior rooms 
of cold storage buildings, and I have put up such partitions 23 feet high, consisting of two 
courses of pure cork sheet with a cement core between and finished with one-half inch cement 
each side. These are giving good service to-day after being in use for the past seven or 
eight years. In one case that I know of, apples in barrels were piled against them 14 
feet high, the barrels resting on the side so that the thrust came solidly against the cork 
partitions. I do not believe a wood partition would stand that strain. 
“Turning now to the question of durability of the balsa wood and its liability to take 
up moisture after a long time in service, I want to cite the behavior of pure compressed 
cork sheets in this regard as showing what can be expected from that material and what 
balsa wood must do to equal it. 
“In 1894, which you will note is over twenty-two years ago, I furnished the sheet cork 
insulation for the American built ocean liners St. Louis and St. Paul. Some three years 
ago the spruce sheathing in the St. Louis beef storage room had rotted out and had to be 
renewed, and when it was taken down her chief engineer reported that the cork sheets back 
of it were sound and bright as when they were put in the vessel twenty years before. Dur- 
ing the last two years I have crossed the ocean three times on the St. Paul. I have talked 
to the chief engineer and have inspected the cold-storage rooms. He tells me that her insu- 
lation is still in first-rate shape and the rooms are holding temperatures beautifully; the only 
trouble they have had has been in the overhead insulation of the rooms, which in the St. 
