Mar. 30, 188S,] 



SCIENTIFIC NEWS. 



297 



FILTER FOR LUBRICATING OILS. 



IN consequence of the greater heat developed by gas 

 and petroleum engines, compared with steam 

 engines, the former require a liberal allowance of oil to 

 lubricate the piston and slide-valves. It is, moreover, 

 especially important that the lubrication should be con- 

 stant and automatic, as engines of this type are so often 

 left working without the presence of an attendant. A 

 considerable quantity of oil drips from the working parts 

 of the engine, and this is usually collected in tins or pans, 

 .but in the state in which it leaves the engine it is too 

 dirty to be used again for purposes of lubrication. 



According to La Nature, Mr. E. Ducretet has devised 

 an oil-filtering apparatus, which he attaches to the 

 engine, as shown in the accompanying illustration. M is 

 the cylinder of the engine, and G the exhaust-pipe, 

 through which the hot products of combustion escape. 

 Around the pipe G is fixed an outer pipe T, which passes 

 through a tank F containing oil to be filtered. The 



filter prtjper I is also placed in the oil tank F, and 

 the action is as follows : the pipe T becomes heated by 

 the hot exhaust-pipe G, and so communicates heat to 

 the oil in the tank F. As the oil expands with heat it is 

 forced through the filter I, and then it runs off into a can 

 at the bottom. 



The arrangement appears to be simple, and little 

 likely to get out of order, provided the pipe T is not 

 allowed to become hot enough to burn or vapourise the oil, 

 which it certainly would do with the larger sized engines 

 if it were too close to the exhaust pipe, G. 



In the course of his experiments, Mr. Ducretet has 

 found that mineral oils are the best, if of good quality. 

 They are the cheapest, they do not oxidise the metal, 

 they are not readily decomposed, and when filtered they 

 can be used over ar.d over again. 



A Rich University. — The University of Leyden is 

 said to be the wealthiest in the world, tfs real tstale is 

 valued at about _^8oo,ooo. 



THE DOTY LAMP. 



THE lamp shown in the accompanying illustration is 

 intended for out-of-door use for such purposes as 

 the lighting of engineering and shipbuilding yards, of 

 railway goods yards, docks, contractors' works, etc. It 

 is, in fact, a rival of the " Lucigen " lamp, which was 

 fully described at the Society of Arts in December last. 

 The apparatus consists of an iron cylinder or drum 



which contains a supply of fourteen to twenty gallons of 

 mineral oil, according to the size of the lamp. On the 

 top of the drum is a coil of pipe, one end of which dips 

 into the oil in the drum, and the other end terminates in 

 the middle of the coil and acts as a burner. A small 

 air-pump is fitted to the drum for the purpose of apply- 

 ing pressure to the oil, so as to drive it through the 

 coil. 



The first operation is to pump in air above the sur- 

 face of the oil until there is a pressure of 10 to 15 lbs. 

 per square inch. The coil is then heated by burning 

 round it a little cotton waste or other inflammable 



