632
T H E J O U R N A L OF . I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
ward and back on C C’. Set-screws are used in u p and down adjustments, but are not necessary in forward and back adjustments, provided the sliding members fit the supports reasonably snug. Rings, c, for supporting flasks are of iron and of the straight stem type. They are attached to the rod D D’ with fasteners, d.
Vol.
IO,
NO.8
This method of draining has given the most uniform results. The time of absorption in seconds is noted on t h e stop watch from t h e first contact of the oil with the blotter until the complete absorption has taken place, It is plainly visible in reflect3d light. which is essential t h a t the comparison be made under like conditions. Blotters from the same package run very uniformly if of high quality; but since t h e test is s o easily made, several results should be averaged. If different pipettes are used for each oil, they should have approximately the same time of delivery for a given liquid. When oils are too viscid a t the temperature of comparison, they may be reduced in viscosity with a small but definite volume of solvent, such as kerosene, or with some other low viscosity oil. CRANE& COMPANY DALTON, MASS.
AN ASPIRATOR B y J. M. JOHLIN Received April 17, 1918
F F‘ is a pipe with outlet in the rear t o hood suction. Holes, e, are of sufficient diameter t o admit the mouths of digestion flasks and act as supports for the same. This pipe should have a slight fall with an opening a t the lower end and drain, f , for carrying off condensation acid. . DEPARTMENT OF CHEMISTRY
N. Y. STATECOLLEGE OF AGRICULTURE, CORNELL UNIVERSITY ITRACA, NEWYORK
RELATIVE VISCOSITY OF OILS AT R O O M TEMPERATURE By C. FRANKSAMMET Received April 13, 1918
Oftentimes it is desirable t o arrive at a relative expression for the viscosity of oils without having recourse t o t h e elaborate apparatus and means for determining the absolute viscosity. A rapid procedure which has proven satisfactory for a relative determination is based on the time of absorption of an oil when dropped upon blotting. paper under uniform conditions. , A piece of heavy weight blotting paper, about three inches square and having a rapid absorption,l is supported by a beaker so t h a t the absorbing area is not in contact with the support, as such contact would interfere with the absorption. The oils t o be compared are brought t o room temperature, then 0 . 5 cc. of oil is withdrawn by a I cc. pipette, and allowed t o flow onto the blotter with th.: end of tha pipettz held in the surface of the oil. The pipette is then withdrawn after a few seconds draining, with a certain amount ofdoil still remaining in the end by capillarity. 1
Reed, THISJOURNAL, 10 (1918), 44.
An aspirator which has been found convenient can be easily made from a large bottle, a few rubber stoppers, and a few pieces of glass tubing, as illustrated in the accompanying figure. Methods of operating the aspirator suggest themselves. Through the tube b the bottle B can be either filled with water or emptied again. When the water cannot be forced out by pressure but must be siphoned, a rubber tube may be used as an extension. Tube a serves as an intake or outlet for the gas. The gas is displaced from B by allowing a capillary stream of water t o flow This arrangement into c from e. operates on the principle oL a constant-level water bath, the side neck d carrying off any overflow. The outlet of e should be small or the stream of water will carry air bubbles into the aspirator. The outlet of a should be sufficiently above c t o prevent water from flowing through it when all gas has been displaced. The force of the stream of water flowing into c generates a pressure slightly greater than that of the water column in t. This type of apparatus is far less clumsy and less top heavy than is the average form of aspirator; a considerably increased pressure can be developed without adding materially t o the weight of the apparatus or without decreasing its stability; opzrating on the principle of the constant level bath, thz aspirator nkeds no attention during operation until all the gas within the apparatus has been displaced. SYRACUSE UNIVERSITY SYRACUSE, N E W YORK
