\ 
ARTIFICIAL REFRIGERATION AND ICE MAKING. XXXVII. 
years in conjunction with the late Mr. T. S. Mort, and his machines 
at Paddington quite supplanted the Harrison ether machine in 
George Street. Many thousands of pounds were spent by Mr. 
Mort in experiments, not only with the ordinary absorption 
system, practical improvements in which were patented, but on 
& compressed air system, L. R. No. 181 of 1868; an absorption 
system assisted by a pump, L.R. No. 216 of 1869; and on a 
system for using nitrate of ammonia ; all under the direction of 
Mr. Nicolle. The first compression machine designed in New 
South Wales for the use of anhydrous ammonia was patented by 
the author (No. 887 of 1880) and called The Colonial Freezing 
Machine, it embodied many devices which are now in general use. 
_ In 1885 the late Mr. W. G. Lock, engineer to the Fresh Food 
and Ice Co. of Sydney, patented a compound compressor for 
ammonia (L.R. No. 1729) consisting of two single-acting high and 
low pressure pumps side by side, very similar to the high class 
Machines now being made by the “ York” Manufacturing Co. 
of York, Pa. U.S.A. In 1881 the author designed the com- 
pressed air machine illustrated by Fig. 3, which had compound 
expansion and was specially intended for use by untrained men in 
the country where water for condensation was very scarce. This 
machine has worked successfully ever since, and will still deliver 
air at 50° below zero. 
Great numbers of patents have since been issued in New South 
Wales to local en gineers for compressers of more or less originality, 
and for other details of refrigerating machinery, and it must not 
be forgotten that Mr. J. D. Postle, by his New South Wales 
patent No. 180 of 1868, was one of the first persons in the world 
to understand and patent the use of an expansion cylinder in a 
cold air machine by which some of the heat held by the air is con- 
verted into work and a low temperature produced. It will thus 
be seen that New South Wales has, in the past, done a large 
_ Share of the work by which the refrigerating machinery of the 
_ World has been brought to its present perfection. It is probable 
that, in the United States, the development of the ice machine 
