104 ANNUAL OF SCIENTIFIC DISCOVERY. 



EXPERIMENTS ON LUBRICATION. 



A careful experiment, made on the Michigan Central Railroad, in regard 

 to the comparative value of whale and metallic oils, resulted in showing a 

 great difference in favor of whale-oil. Running a single train 103 days, one- 

 half of the journals were lubricated with whale-oil, consuming 28} gallon?, 

 costing GO cents per gallon ; the other half with metallic oil, consuming 27 

 gallons, costing $1.34 per gallon. Railroad Register. 



IMPROVED METHOD OF TANNING. 



The Scientific American, translates from the Bavarian Journal of Arts and 

 Trades the following account of a new method of tanning, recently intro- 

 duced into Bavaria, by M. Knoderer. 



It is well known that, by keeping the hides and the tanning substance from 

 coming in contact with the air, the tanning process is materially facilitated. 

 In order to effect this practically, the only way is to carry on the tanning in 

 vacuo. 



The vessel in which the tanning substance is kept has to be made air-tight, 

 and, at the same time, no metal can be used except the very expensive one, 

 copper. Iron, as well as zinc, is affected by the tanning substance; wood 

 can only be used if its pores have been stopped by some varnish, which 

 effectually prevents the air from entering the vessel after it has been pumped 

 out. 



M. Knoderer employs a cylinder, or barrel, rendered air-tight, and fitted 

 with man-holes, air-pumps, etc., and an apparatus by which a rotation can 

 be imparted to it. The operation of tanning is then carried on as follows: 

 When the hides are taken from the wash, all the water contained in them is 

 expelled by a powerful press. This done, they are placed into a barrel, to- 

 gether with the necessary amount of bark, or other tanning substance. A 

 sufficient quantity of water is added to keep the contents of the barrel moist. 

 The man-hole is now closed, and the air pumped out as clear as possible. As 

 the rarefi cation of the air in the ban-el proceeds, the pores of the hides are 

 opened and prepared to receive the tanning substance. When the air has 

 been rarefied as much as possible, a suitable quantity of tanning solution is 

 admitted by means of a pipe, which passes through one of the trunnions on 

 which the barrel is suspended. The barrel is then rotated half an hour, ac- 

 cording to the quantity of hides in the same. After two or three hours' rest, 

 the rotation is continued for a longer time; and so on, diminishing the time 

 of rest and prolonging the time of rotation, until at last the rotation is con- 

 tinued to the end of the operation. 



By thus combining three actions the rarefication of the air, whereby the 

 pores of the hides are opened, and the formation of gallic acid is prevented ; 

 the rotary motion, which facilitates the extraction of the bark, and which 

 produces a continuous fulling of the hides; and the increased temperature 

 which is produced by the motion, and whereby the combination of the gela- 

 tinous matter contained in the cellular texture of the hides with the tanning 

 substance is greatly facilitated; by this combined action, the tanning of the 

 hides is effected to perfection, and with a saving of time, which is fully 

 established by the folio whig table, based on actual experiments : 



