TEST FOR GUMMING QUALITY O F LUBRICATING OILS.
I 2
3
{ White-brown semi fluid ) 0.919 80.2 Dark brown { semi liquid } 0.916 54.0 { y e l l ~ ~ J ~ w n ) 0.922 71.0 1000
4 5
Golden brown 1 { nearly solid / Very like. 4
46.0
95.8 75.1
52.1 108.5 82.5 54.7
114.0
e . . .
82.0
467
32.5-33.5 72.9 30.0-31.0
72.3
86.3 83.7 25.0-26.0 78.7
c.
0.798 48.0 54.2 112.9 79.9 81.8
30-31
80.4
0.799 61.0 53.5 111.5 78.8 78.2
34-35
82.1
Neatsfoot oils : the samples are fairly concordant with the e x ception of No. 3 : the gravity and Maurnen6 test are higher than those of the others ; a s no adulterant could be proved, it is supposedly genuine. Tallow oils : the results here, upon oils from different sources, are remarkably concordant. Horse oils : as was expected from their different appearance, these show a considerable variation ; the Valenta test is of no use whatsoever here ; No. j came from a young horse ; nothing is known about the others. Were either of these oils used to adulterate neatsfoot, the horse oil would raise the Mailmen6 and iodine values, and the titer test; tallow oil would lower the Maumene, and iodine values, and raise the titer test quite considerably.
A T E S T FOR T H E GUMillNG QUALITY OF LUBRICATING 01LS. BY AUGUSTUSH. GILL.
s
Received February 3, q a z .
OME years ago in studying the Elaldiu test for oils, a few of the mineral lubricating oils were included, and it was noticed that those which deposited the most tar” apparently changed the most in use. T h e test, other than a repetition with different oils, lacked confirmation as to its value except in one case. I t was noticed that with a 25’ paraffin oil the outside of the can containing it-where it was exposed to the air in thin layers-was covered with a skin closely resembling that produced
468
G U M M I N G QUALITY OF LUBRICATING OILS.
by linseed oil. T h e object of this work was to show that there is a connection between the amount of change ( " tar") arid the quantity of oxygen absorbed. T h e gumming test was applied after the manner of the Elaidin test by treating j grams of the oil in a cordial glass with I I grams of Roth's liquid (iiitrosulphuric acid) the two being thoroughly stirred together and cooled by immersion in a pan of water at IO'-I j oC. Brownish spots or, in case of a bad oil, masses form around the edges and become red in the course of two hours. T h e nitrosulphuric acid is prepared by saturating sulpliuric acid of 46' B & . ,containing a few drops of nitric acid, a t 0 ' with nitric oxide. T h e quantity of oxygen absorbed was determined by sealing 5 to I O grams of the oil in a flask aiid heating i t to SOo-IOjo,the flask being occasioiially shaken. T h e oil was weighed into the flask, care being taken that noiie touched the neck ; the neck was drawn down to a loiig thin-walled capillary, the flask allowed to cool at z o o , and then quickly sealed in a small blast-lanipflame. After heating about I O O Iiours tlie flask was allowed to cool to 2 0 ° , the capillary brokcii under water and the inflowing water weighed. This represented tlie number of cubic ceiitimeters of oxygen absorbed from the air. T h e results are sliorvn iii the table. I t was thought that possibly a difference between these oils might be :ho~vii by either the Lroniiiie, iodine or lIaumeii6 tests : the differences were, honrever, so slight as to show that these could not be used as a means of distinguishing betweeti the oils. The results should lie compared crosswise of the table, as the temperatures, time of exposure, aiid amount of sliakitig varied with each test. TVith the eiigiiie oils the niiiount of tar formed seems to bear a close relation to the quantity of oxygen absorbed; this does iiot apparently hold true of tlie spir:dle oil tested. 2.
3.
I 25O parKed 1ul)riYo I enso. I Name uE oil. ...... 1 affiti. catitig. pine. spin tile. Appearance in gum- I Dark brown Some dark Dark brown, Medium brown, ining test ....... 1 pitchy cake. pitch. trace of pitcii. no pitch.
cc.
Oxygen absorbed per ICMJ I 45.6 grams oil a t Soo.. .... '( 46.0
[
Oxygen absorbed at SooSgo, 1 2 days. ......... ~
:::
IOj.4
I. 101.6
Oxygen absorbed a t 9 8 O - ! .... I I ~ " ,1 2 days .... Oxygen absorbed a t gs0- $ 188.0 I O ~ O , 1 2 days ........ ( 1 j 0 . 0
........
CC.
ho.0
cc.
12.2
62.3
1j.o
....
....
121.0
jj.6 36.a
....
....
42j . 0 402.0 238.0 27 2 . 0
34.1
111.0
104.0 65 .o
....
CC ,
~Th.0 413 15 . 9. 5 160.9 54.6 j0.J 321.0 320.0 251.0
....
