The fatty oils and fats are composed of either oleic, margaric or palmitic and stearic acids, which, when treated with caustic soda, form compounds soluble in water. Precipitated with mineral salts, such as sulphate of alumina, magnesia, lime or acetate of lead, etc., they form insoluble compounds, which are only soluble in other fatty oils or petroleum oils. In this state the oils possess uncommon lubricating power, without the injurious effect the otherwise free fatty acids would exert on the metal of which the machinery requiring lubrication is made. They form the foundation of the manufacture of the "Valve-Oleum" Oils ("Valve-Oleum" is their trademark), patented by the author, and they combine the excellent lubricating qualities of fatty oils with the great cleanliness and diffusing qualities of mineral oils. To manufacture the valve-oleum oils, lard oil, cottonseed oil, neatsfoot oil or lard-grease, or even fish oils, can be used to make the "Valve-Oleum " Gelatine, the mineral castor and the so-called honeydrop engine oils.

Neatsfoot oil is used to make the finest grades of "Valve-Oleum" cylinder oil, and for heavier and coarser grade cake-tallow can be used. Extra strained white lard oil or extra prime lard-grease is used to make the so-called "Valve-Oleum" white castor oil and the oil known as "Commercial Castor Oil," a cheaper substitute for the more costly castor bean oil. The oleate, marga-rate or palmitate, or stearate of alumina, is the combination preferably used in the manufacture of the "Valve-Oleum" Oils, although oleate of lime and oleate of lead can be used in like manner, the latter especially in the manufacture of paints, paint oils and factitious linseed oils.

Oleate of alumina is made in the following manner:

A solution of caustic soda is first prepared by dissolving caustic soda (some 160 pounds for a batch of 1,200 pounds of oil or fat) in about 90 gallons of water, thus making about 110 gallons of a caustic soda lye of from 22° to 23° Baume. If the lye is freshly made, it will be heated by the chemical action which takes place between the dry soda and the water. In that case, if fat or tallow is to be used, it is only melted with heat so that the combined temperature of the fat with that of the hot lye will not exceed 250° F. If the lye has been previously prepared and has become cold, the temperature of the oil or fat should be increased to about 200° F.

Table of Proportions of Caustic Soda to Grease or Oils for oleate of soda in the manufacture of the Valve-Oleum Lubricating Oils

Pounds of fat or oil

Require of Caustic Soda

Dissolved in Water

Produces of Lye

Of specific gravity

8 (1 gl.)

17 ounces

4| pints

5f pints

23° Be.

40 pounds

5 1/3 pounds

3 gallons

3 1/2 gallons

"

50 "

6 1/2 "

3 3/4 "

4 1/2 "

"

100 "

13 1/2 "

7 1/2 "

9 1/8 "

"

150 "

20 1/4 "

11 1/4 "

13 3/4 "

"

200 "

26 1/2 "

15 "

18 1/4 "

"

250 "

33 1/4 "

18 3/4 "

22 7/8 "

"

800 "

39 1/2 "

20 1/2 "

27 3/8 "

"

350 "

46 1/4 "

26 1/4 "

32

"

400 "

(50gls.)

53 "

30 "

36 5/8 "

"

450 "

59 1/2 "

33 3/4 "

4l 1/8 "

"

500 "

66 "

57 1/2 "

45 3/4 "

"

550 "

72 1/2 "

42 1/2 "

50 1/4 "

"

600 "

79 "

45 "

54 7/8 "

"

650 "

85 1/2 "

48 3/4 "

59 3/8 "

"

700 "

92 "

52 1/2 "

64 "

"

750 "

98 1/2 "

56 1/4 "

68

"

800 "

105

60 "

73 1/4 "

"

850 "

11 2 1/2 "

63 3/4 "

77 3/4 "

"

900 "

11 8 1/3 "

67 1/2 "

82 1/4 "

"

950 "

125 "

74 1/4 "

86 7/8 "

"

1000 "

131 1/2 "

75 "

91 1/2 "

"

1200 "

"

(150 gls.)

160

90 "

110 "

"

While constantly stirring, the lye is slowly run into the oil or fat and the stirring continued until the mixture has become a soapy, mushy compound and has assumed a perfectly neutral and soapy taste to the tongue. This will be accomplished in from one to two hours, depending much on the quality of the fat or oil, being fresh or old. The resulting product is the oleate of soda, which is next dissolved with boiling water. Previously from 550 to 600 pounds of alum (sulphate of alumina) are dissolved in about 6 barrels of boiling water, and when all is dissolved and the solution is perfectly clear, it is, while constantly stirring, gradually run into the solution of oleate of soda, enough of it until the oleate of alumina thus formed floats as a pasty compound on a clear, watery solution of sulphate of soda, the sulphuric acid of the sulphate of alumina having united with the soda of the oleate of soda, while the oleic acid of the oleate of soda has united with the alumina and formed "oleate of alumina." The whole mass is now started boiling and if any lathery foam still appears on the surface, some more alum solution is added, until all the foam has disappeared and the liquor remains perfectly clear. Next one barrel of 25° paraffine oil is added, and the whole briskly boiled and stirred for about one hour. Then the steam is turned off and stirring is stopped and the pasty mass allowed to subside over the clear watery liquid. This is then drawn off and replaced with fresh boiling water, and the boiling and stirring are resumed and several times repeated, until all taste of alum or sulphate of soda has been removed. The last wash-water is then drawn off, and heating and slow stirring continued for a short time, and then discontinued, to allow of some more water, freely separating, to be drawn off from underneath the pasty mass. Heating and stirring are now again resumed, keeping the heat at a high and uniform temperature, until the pasty mass becomes turned from its white to a brownish color and has become perfectly clear and transparent and is pulling heavily, like molasses candy.

When a small sample of the mass, thrown onto a glass plate, shows perfectly clear and transparent and free from all moisture, paraffine oil, which has been previously heated to about 140° to 150° F. and kept at that temperature until all hygroscopic moisture and adhering light hydrocarbon vapors have been expelled, is then added by slowly running it into the batch while constantly stirring and keeping the temperature at from 150° to 160° F. for from two to three hours or more.

To make the "Valve-Oleum Gelatine" not too heavy and so as to allow it to be drawn off into barrels, but still warm enough to prevent it from chilling, from 3 1/2 to 4 barrels of the paraffine oil to every barrel of fat or oil used in the making of the aluminate, are required.

To make a heavy and stringy mineral castor for use on heavy bearings and machinery, some 40 to 45 barrels of paraffine oil to a 1,200-pound (or 3 barrels) batch of fat or fatty oil, are required, and more if a lighter grade is desired.

"Valve-Oleum" engine, so-called "Honey-drop" oil, is made in precisely the same manner, but in order to cut the stringy nature of the heavy castor oil to a honey-drop one, better adapted for oiling engines and lighter machinery, from 30 to 40 gallons of degras to a 1,200-pound batch are added together with the barrel of par-affine oil when boiling the compound, after the precipitation with alum and before the repeated washings.