xl. ABSTRACT OF PROCEEDINGS. 
production of cement during the last thirty years, the 
lecturer proceeded to describe the various improvements in 
the mills for grinding together the chalk and clay, and in 
the kilns for converting the “‘slurry”’ into “‘slip’’ and finally 
into “‘clinker.’’ The gradual improvements in the kinds of 
kiln from the primary Bottle type to the Ransome rotary 
kiln were illustrated by means of diagrams. It was to the 
invention and improvements in the rotary kiln that made 
the increased production of cement possible. The evolution 
of the method of grinding the “‘clinker’’ was shown by the 
changes from the old stone mill to the Krupp combined 
erushing, pulverising and sifting rotary mill. HKmphasis 
was laid upon the fact that the efficiency of a cement 
depended largely upon its fine state of division as compara- 
tively large particles are inert and behave like sand. 
The lecturer dealt with the varieties of specifications 
laid down by the various State Governments, and as con- 
fusion tended to retard the industry, he suggested that 
scientists should move in the matter of obtaining a stan- 
dardisation of the specifications. 
Mr. MorRIson followed with a description of the physical 
properties of cement as indicating its value. He gave the 
various standards adopted by the New South Wales Govern- 
ment, and the methods used for testing cement. The 
breaking strength was demonstrated by means of the 
standard apparatus. 
. The Chairman in thanking the lecturers, mentioned that 
the question of standardisation was part of the scheme of 
the Institute of Science and Industry. A discussion upon 
the lectures was contributed by Dr. R. K. MURPHY and 
Mr. W. M. HAMLET. 
Monthly Meeting, September 9th, 1918. 
Mr. W. T. WILLINGTON in the Chair. 
