hf —-= owe! eee eee 
170 LAWRENCE HARGRAVE. 
authorities, sufficiently high to destroy all germs likely to be in- 
jurious to health. If this object aimed at is attained by present 
investigations, I feel sure that the ventilation of the Sydney 
sewers will leave very little room for complaint. 
FLYING-MACHINE WORK AND THE #I. H.P. STEAM 
MOTOR WEIGHING 3thibs. 
By Lawrence HaARrGRAVE. 
[With Plates V. to XIII. inclusive. | 
[Read before the Royal Society of N.S. Wales, August 3, 1892. ] 
SIncE July Ist, 1891, a quantity of experimental work has been 
done that will be of interest to those who see the near approach 
of the successful navigation of the air. 
No. 15 motor may be passed over with the statement that it 
was intended to drive two screws in opposite directions by bands 
from a turbine. The turbine to be worked by the products of the 
combustion of nitrate of ammonia, charcoal and sulphur. A con- 
siderable expenditure of time resulted in the turbine remaining 
stationary. 
After long delay some pure aluminium was procured with a. 
view to ascertaining whether the receivers for the compressed 
air could be made out of it lighter than the tinned iron plate 
ones. A receiver was made 233 ins. long and 5:4 ins. diam. of 
aluminium plate ‘02 ins. thick. 3 ins. x jin. rivetting strips 
were insufficient to make tight joints; it weighed twenty-six 
ounces, and 80 ibs. per square inch water pressure blew out one of 
the ends ; the fracture took place at the bend of the flange, not 
along the line of the rivets. 
