160 REFRIGERATION AND REFRIGERATOR INSULATION ON BOARD SHIP. 
stuffing boxes. I have inquired of large manufacturers, and one firm with an output of 6,500 
machines to date, 3,000 with piston rod and 3,500 with crank-shaft packings, states that in 
the case of piston rods they do not use the type of floating packing the author recommends. 
These 3,000 machines are working perfectly satisfactory, without any undue wear on the 
piston rods, and have the lantern oil space put up in the usual manner of the 3,500 machines 
with a crank-shaft packing; and in 4,000 similar machines manufactured by another firm 
(in all 7,500 crank-shaft packed machines) there was not one that ever had a crank-shaft 
replaced due to the wear of the packing. Furthermore, leakage would be across the lines 
of wear with the crank-shaft packing, and along the lines of wear with the reciprocating 
rod packing, making it much easier to pack tight a worn crank-shaft than a worn piston 
rod. 
Referring to the dumb-bell type of machine, of the all-enclosed type, I would ask the 
author if they have experienced any necessity for renewing the old oil? The oil, as I un- 
derstand it, is locked up in the machine with the refrigerating fluid. It would appear to me 
that the oil would lose its lubricating properties in the course of time through continuous 
friction and wearing down of the bearings, and that the resulting grit would get into the oil, 
unless there is some means of filtering it in circulation. Furthermore, to recommend a 
machine of the Audiffren-Singrun type on a vessel, where you have skilled engineers, is to 
expect the owners to rely entirely on the satisfactory performance of the machine as deliv- 
ered to them by the makers, with the knowledge that their engineers are absolutely unable to 
help themselves in the event of trouble. This does not seem to me to be a good proposition 
in a case where you must have skilled mechanics on hand at all times. If it were possible 
to open the machine and effect repairs in the event of trouble, things would be different; but 
as I understand the situation, if the machine gives trouble it must in its entirety be re- 
moved from the vessel, sent back to the manufacturers, repaired and charged, and returned 
again to the vessel. In my opinion that means it would be necessary, on ocean-going vessels, 
to carry two complete units, either one of which is capable of performing the full cooling 
duty. That seems to be a prohibitive proposition, and much more serious than carrying a 
spare flask of ammonia or a couple of flasks of carbonic acid-gas, which can be obtained in 
practically any civilized port in the world. 
THE CHAIRMAN :—Is there any further discussion? If not, I will call on Mr. Massa to 
close the discussion. 
Mr. Massa :—In regard to putting the insulation on the side plates of the ship, I did 
not refer to that particular location. I had in mind the small refrigerators cooled by small 
machines. However, as a matter of fact, 1 have seen, on several submarines, sheet cork put 
on the shell of the ship, and apparently put on in perfect condition. While I am not a 
marine man, it would seem to me that would be quite as difficult a place to put the cork as 
any other place on the ship. 
As to a comparison between the sheet cork and the granulated cork, we, of course, real- 
ize that the granulated cork is, we will say, half as good as the sheet cork. When you come 
to deal with small refrigerators, such as I had in mind in this paper, the addition of 4 
inches of thickness on all the surface means an astonishing percentage of volume you are 
taking up, and in ship work, unless I am very much mistaken, space is at a premium. If 
Mr. Williams will compare the cost of a cubic foot of storage space on board ship, 
