PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 525 



all the requirements, must satisfy ten distinct conditions, which I 

 will enumerate. 



I have gone over this labor more as a labor of love than of 

 prolit, being persuaded that the subject is most important, more 

 so than the majority of people are aware of; we only have to 

 take in account the large amount of useful power lost all over the 

 world, even in the best constructed machinery, by inferior lubri- 

 cators, an amount of which, easily two-thirds, could be saved ; 

 also tlie ruinous etfect on the machinery itself by inferior lubrica- 

 tors, heating it, wearing it out, throwing it much sooner out of 

 repair, and causing it to last not half the time that it would do 

 "vvith perfect lubricators. 



The conditions required of a perfect lul)ricator are as follows : 

 1. It must not freeze or solidify at the temperature of our coldest 

 winter days, say 10° below zero, Fahr., as is the case with sperm and 

 lard oils, which freeze, some at 40°, some already at 50°, and 

 even at 60° above zero. 



2. It must not dry and form a gummy crust, like linseed oil, 

 which has the virtue of not freezing, before reaching 8° or 10° 

 below zero, but which is only an excellent lubricator as long as 

 it is fresh ; it is, however, a drying oil, and soon forms a crust. 

 Fish and rape oil will do the same, only it takes much longer 

 time before they gum. 



3. The oil must not be a compound of fatty acids with glyce- 

 rine, as all those oils become rancid l)y exposure to the air, which 

 rancidity is only a decomposition b}^ which the acid is set free ; 

 this acid acts on metals like brass, corrodes it, as is seen in the 

 green color of many lubricators when in contact with brass ; all 

 vegetable and animal oils have this chemical composition, and 

 therefore are objectionable on this account. 



4. Those same oils will, for the same reason, produce spon- 

 taneous combustion when the woolen or cotton rags used for clean- 

 ing the machinery are saturated with it, and accumulate in a closet 

 or l)ox ; the action of this oil on the tibrcs of the rags produces a 

 steadilj^ increasing heat, and has been the cause of many a tire, as 

 is universally known. I observe in the annual of Alechanical 

 T ecJinology (Berlin, 1863, page 47) that Prof. Bolley draws the 

 attention to the fact of cases having been found wdiere the fatty 

 acids of the lubricators came with the feed water in the steam 

 boiler, and, combining with the lime in the water, increased the 

 incrustation considerably. 



