Abbreviated column headings:

Qty. Air: Quantity of Air at 45 lbs. Pressure required per Ind. H.P. per
Hour.

Cost/Hr.: Cost per Hour at 5d. per 1000 Cubic Feet.

Cost/Hr. w/rebate: Cost per Hour with Rebate when Profits reach 26 per
Cent.

Cost/Yr.: Cost per Annum (2700 Hours) at 5d. per 1000 Cubic Feet.

Cost/Yr. w/rebate: Cost per Annum with Rebate when Profits reach 26 per
Cent.

Abbreviated row headings:

CASE 1.--Where air at 45 lbs. pressure is re-heated to 320° Fahr., and
expanded to atmospheric pressure.

CASE 2.--Where air at 45 lbs. pressure is heated by boiling water to
212° Fahr., and expanded to atmospheric pressure.

CASE 3.--Where air is used expansively without re-heating, whereby
intensely cold air is exhausted, and may be used for ice making, &c.

CASE 4.--Where air is heated to 212° Fahr., and the terminal pressure is
11.3 lbs. above that of the atmosphere