Frictional test of Mineral [Unknown] Oil, on March 27 to 29, 1880. Sample nearly two years old. Rev. per min. 475.55, 5 lbs. pressure per sq. inch. Velocity of rubbing surfaces, 534.99 feet No. trials 10.

per minute.

No. of sample 1.

Frictional test of Leonard & Ellis' Valvoline Spindle Oil, on April 9 and 10, 1880. Rev. per min. 445.52, 5 lbs. pressure per sq. inch. Velocity of rubbing surfaces 501.21 feet per minute. No.

of sample 2. No. of trials 5.

Frictional test of John P. Squire & Co., Lard Oil, on April 9 to 14, 1880. Rev. per min. 501.10, 5 lbs. pressure per sq. inch. Velocity of rubbing surfaces, 563.74 feet per minute. No. of sample 3. No. of trials 7.

Frictional test of No. 25 A Bleached Winter Sperm Oil, on April 15 and 16, 1880. Rev. per min. 500.92,5 lbs. pressure per sq. inch. Velocity of rubbing surfaces, 563.53 feet per minute.

Number

COEFF.

Frictional test of 25 B Sperm Oil, on April 16, 1880.

Rev. per minute 501.81, 5 lbs. pressure per sq. inch. Velocity of rubbing surfaces 564.60 feet per minute. No. of sample 5. No. of trials 3.

Frictional test of 25 C Sperm Oil on April 19, 1880. Rev. per minute 517.59, 5 lbs pressure per sq. inch. Velocity of rubbing surfaces 582.28 feet per minute. No. of sample 6. No. of trials 2.

TEMPER

ATURE.

TEMPER

ATURE.

VeNo. of

Frictional test of Downer's Light Spindle Oil, on April 17 to 19, 1880. Rev. per min. 500.21, 5 lbs. pressure per sq. inch. locity of rubbing surfaces 562.73 feet per minute. sample 7. No. of trials 4.

TEMPER
ATURE.

Frictional test of Downer Oil Co., 32, Ex. Machinery Oil, on April 20 and 21, 1880. Rev. per minute 503.91, 5 lbs. pressure per sq. inch. Velocity of rubbing surfaces 566.81 feet per minute. No. of sample 8. No. of trials 6.

Frictional test of Aiken & Swift Bleached Winter Sperm Oil, on April 22 and 23, 1880. Rev. per min. 456.09, 5 lbs. pressure per sq. inch. Velocity of rubbing surfaces 513.10 feet per minute. No. of sample 9. No. of trials 6.

Frictional test of Downer's Heavy Spindle Oil, on May 23, 1880. Rev. per minute 503.43, 5 lbs. pressure per sq. inch.

Velocity

of rubbing surfaces 541.57 feet per minute. No. of sample 10.

No. trials 3.