662 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



Table VI. — Blou'crs in nsc. 



Kind of blowe 



Volume of 

 blustper 

 revolution. 



Number 

 of revolu- 

 tions per 



minute. 



I Extreme 

 Volume of limits of 

 blast per i pressure in 

 minute. inches of 

 mercury. 



B 

 B 



Baker's, No. 5.. 

 do 



Baker's, No. 4i 

 Baker's, No. 4. 

 Baker's, No. 5J 

 Baker's, No. 5.. 

 Baker's, No. 4i 

 Baker 8, No. 5J 

 Baker's, No. 5- 

 Baker's, No. 4J 

 Baker's, No. 5J 

 Baker's, No. 6 . 

 Eoot's, No. 5 .. 

 Baker's, No. 5. 

 Baker's, No. SJ 



do 



Baker's, No. 5. 

 Baker's, No. 4S 

 Baker's, No. 5. 

 Baker's, No. 4i 

 Baker's, No. 4. 

 Baker's, Nc. 5 . 



16i 

 25 

 ICi 



Cubic feet. 

 2,000 

 2,250 

 1,465 

 1,060 

 2, 250 

 2,200 



1, 320 

 2,400 

 2,000 

 1,782 

 3,000 

 3,825 

 3,000 

 2,125 

 3,000 

 2,400 



2, 000 

 1,320 

 2,125 

 1,320 

 1,080 

 2,000 



ItolJ 

 Itoli 

 1 toli 

 1 toli 

 itolj 

 itoli 



1 



1 

 itoli 

 itoli 

 itoli 

 itoli 

 itoli 



The liorseiiower required to drive the blower.s at a giveu rate is obtaiued by the 

 following emi^irical formula : V being the volume of blast in cubic feet to be deliv- 

 ered in one minute; P, the pressure shown by the manometer in the blast-pii)es, 

 expressed in ounces i>ev square inch ; H, the horse jjower ; and /(, the power required to 

 overcome friction, varying with the size of the blowers : 



„ FxPxO.003 ,, 

 E= ^^ + h 



The power required to run one of the blowers is proportionate to the pressure of 

 the blast, volume delivered, and friction; blowers of different sizes require the same 

 power when they deliver the same volume of blast. 



Baker's rotary lorccd-biast blower — These blowers are manufactured by Messrs, 

 Wilbraham Brothers, of Phihxdelphia. They are compact and constructed on very 

 simple i)rinciples. They deliver a positive blast, the volume of which is ]>roportionate, 

 for each size, to the number of I'evolutions. They hardly ever get out of order and 

 give universal satisfaction in Leadville. (The sketches corresponding to the following 

 description ai-e those of a blower No. 5, taken from the maker's catalogue.) They 

 consist of a cast iron case, A (Figs. 1 and 2, Plate XLIl), strongly ribbed and bolted, 

 rectangular in plan and section, and of an arched top, B. Inside of this works a drum, 

 X>, carrying two tapering arms, C C", which sweep round so close to the interior i)eripbery 

 that no air escapes. There are, besides, in the cast-iron case A two other drums, E 



