REFRIGERATION AND REFRIGERATOR INSULATION ON BOARD SHIP. 161 
especially under present conditions, against the saving by using granulated cork, he will find 
the balance in favor of the more compact insulating material. 
When it comes to a location where space is not so important, nor durability, the gran- 
ulated cork is not only all right but is the thing to use. When you get down into the south- 
west, where they have all kinds of space, you can often use cotton seed hulls which are 
cheaper yet, and satisfactory, 7. e., where you have space to put 24 inches of insulation on the 
sides of a brine tank, 
As to the proper location of the door passing into the refrigerator, that is a thing which 
should be given careful consideration, but it is not always done, and it is to point out the 
difficulty there that I have made the note on the subject which I did. Air locks are, of 
course, the things to use where you have a large box. Frequently, in the smaller refrigera- 
tors, there is no space on board ship to do it. I remember one case where we had good 
luck and there was space for an air lock. Very frequently, however, there is not space for it, 
and you have to do the best you can with the conditions to be faced. 
I am sorry that I spoke of carbonic acid and ammonia in the same sentence. I might 
have had a period between the two. Carbonic acid is a less difficult gas to deal with. I do 
not know that it is worth while going into the difference between the two substances. 
As to the ammonia leakage, we have two companies under the same financial manage- 
ment, where the chief engineer of the one company had an experience with ammonia in the en- 
gine-room, and we cannot get even our machine in his engine-room. The other man has 
never had such experience, and we cannot get our machine into his engine-room for another 
reason. He is absolutely not afraid of ammonia. The man who has had the experience is 
afraid of it. 
As to the difference between the open and enclosed types of machine, I have some pho- 
tographs of crank shafts that have come out of enclosed-type machines, and they do show 
very decided wear. It would seem, further, that the statement of a company that has built 
some seven thousand enclosed-type machines and “never had any trouble with them” is not 
very serious criticism. I do not feel like arguing the point. I think on the face of it that the 
wear is more uniform and more readily taken care of on the piston-rod than on the crank- 
shaft type of stuffing box. As I said in the paper, I know of one line of machines, with 
which I am not connected in any way, where they do use a flexible stuffing box, and the fric- 
tion certainly is very much decreased on these outfits. These machines are used on small 
work where temperatures change rapidly and where the box without this adjustment au- 
tomatically cannot be made to stand up without constant care. 
As to the oil in the hermetically sealed type of machine, that oil is never replaced. Mr. 
Williams is laboring under the very common impression that an oil in some way breaks down, 
as if there were some actual structural change in the oil. We often speak of oil wearing 
out. There are only two things that happen to oil, when you analyze the matter—one is 
that it oxidizes, and the other is that it gets dirty. The oil in the hermetically sealed type 
of machine is not exposed to the air; it cannot be exposed, and neither can it get any dirt 
in it. The machines are cleaned with a degree of care that is almost unbelievable. Until 
I had an opportunity of seeing how it was done, I had no idea of their being handled in 
any such careful way as they are handled. They are absolutely clean—surgically clean— 
and the proof of experience is that that type of machine does stand up. We have had ma- 
chines in this country for about six years now, running right along and giving satisfactory 
service—at least such service that we have never heard any complaint at all—and I remem- 
