ARTIFICIAL REFRIGERATION AND ICE MAKING, LVII. 
foundations, but have one shaft in common with their respective 
cranks at opposite ends set at the angle desired. The former 
(Frick «&c.) is the better mechanical arrangement as it is possible 
under it to make the whole machine complete in itself on one 
foundation. The only way to secure the simplicity which should 
characterise an ideal compressor is to adhere to the straight line 
connection, so that instead of the crank shaft having to take the 
sum of the work represented by the engine and compressor diagrams 
it should only have the difference to deal with. To make this 
clearer, suppose at a particular part of the stroke of a right angled 
machine the force exerted by the engine piston is 1000 bs. and 
the compressor requires 900 ibs. to move it, then the whole stress 
of 1,900 Tbs. is communicated to the bushes of the connecting 
rods and main journals; on the other hand, in a straight line 
machine, doing the same work, the 900 lbs. would be applied 
directly from one piston to ‘he other, and only 100 Ibs. would be 
communicated toth necting rods and journal instead of 1900tbs. 
When the author realised, from a consideration of these facts, 
the great opening that there was for improvements in this direc- 
tion, he set to work to see how they could be brought about, but 
it soon became evident that it was only by making the diagrams 
from the engine and compressor more nearly coincide, that an 
ideal straight line connection could be effected ; asa result of two 
years’ work the machine known as the Antarctic Compressor has 
been devised, which is shewn in section by the diagrams and will 
now be described. 
There is nothing new in compound compression. Mr. Lock’s 
patent of 1885 has been already referred to, and the author — 
designed a large compound air compressor in 1884, which is still 
in the Colony, but most compound —— — a complicated 
arrangement of valves and p to the other, 
and separate stuffing bocas & foe the piston oe of the high sad’ 
low pressure cylinders, 
Now the peculiarities of the Antarctic mews Compressor 
ee eee are :— 
