158 JOHN M. SMAIL. 
with an approved cowl and attached to sides or gable of buildings 
with neat straps &c. The tubes are coated inside with asphaltum 
paint and painted externally with two coats of picked colours. 
The first installation has been in some cases nearly two years in 
operation and although in very exposed situations, have withstood 
very heavy gales of wind which have occurred. Some of the gales 
were severe, the registered velocity in one case being fifty miles 
and in another sixty-four miles per hour, this would exert a pressure 
against the shaft which is unsupported above the wall of the 
house, of 12-5ibs. and 18tbs. per square foot. 
Water sprays— Water sprays in manholes for inducing currents 
of air into the sewers have been tried with very successful results. 
The water is passed down the shaft by a three-quarter inch pipe 
fitted with a patent nozzle, and is spread in the form of a cone. 
A meter is fixed on the main to register the consumption of water. 
The results obtained were as follows: 
Average quantity of water used per hour—213 gallons 
Air passed into the sewer per hour—62,647 cubic feet 
Quantity of water used per diem—9)112 gallons 
Quantity of air passed into the sewer per diem—1,503,528 c. ft. 
The quantity of air passed into the sewer per cubic foot of 
water—1842 cubic feet | 
The cost for water per 1,000,000 cubic feet of air—3/4. 
The quantity of air per cubic foot of water has been raised to 
2,250 cubic feet by improving the nozzle. The sewer was tested 
with the spray working and stopped, the report of the inspector 
shewed that when the spray was working the air in the sewer was 
‘cool and free from odour, and the air currents passing up stream 
from the spray shaft varied from 12,000 to 6,600 lineal feet per 
hour, these figures would represent 115,424 and 113,190 cubic 
feet per hour respectively. JI examined a portion of this sewer 
after the spray had been working some time and found that 
what had formerly been a very wet length was drying up con- 
siderably, the filmy coating which is generally found in large 
sewers where the flow fluctuates, had become dry and was scaling 
