375 



Art. XIII. MISCELLANEOUS INTELLIGENCE. 



I. Mechanical Science. 



1. Effects of an Anti- Attrition Preparation. — A Munich journal 

 reports the following results relative to the advantage obtained by 

 employing a mixture of hog's-lard and plumbago for the diminu- 

 tion of friction in machines. The composition consisted of ten 

 and a half parts of pure hog's-lard, fused with two parts of finely 

 pulverized and sifted plumbago. The lard is first to be melted 

 over a moderate fire, then a handful of the plumbago thrown in, 

 and the materials stirred with a wooden spoon until the mixture 

 is perfect ; the rest of the plumbago is then to be added, and again 

 stirred till the substance is of uniform composition ; the vessel is 

 then to be removed from the fire, the motion being continued until 

 the mixture is quite cold. 



This composition is to be applied to pivots, the teeth of wheels, 

 $"c, in its cold state by means of a brush, and is seldom re- 

 quired oftener than once in twenty-four hours. It was found that 

 the machines employed in certain iron works, cost, in oil, tallow, 

 and tar, as much per week as six florins twenty-nine kreut- 

 zers ; but, upon replacing these substances by the composition 

 described above, the expense was diminished to one florin thirty- 

 eight kreutzers for the same time, 5 lbs. being required for 

 the week's service. Economy to this extent is not to be neglected 

 in manufactories where many machines are in use. — Ann. des 

 Mines •, xi. 79. 



2. Strength of Leaden Pipes. — Experiments upon this subject 

 have been made at Edinburgh by Mr. Jardine at the Water Com- 

 pany's yard. The method followed was to close one end of a piece 

 of pipe, and then throw water into it by a forcing pump attached 

 to the other end, the force or pressure being measured by a gauge 

 belonging to the pump. When the water from the injecting pump 

 first begins to press out the pipe, little or no alteration is observed 

 on it for some time. As the operation proceeds, however, the 

 pipe gradually swells throughout its whole length, until at last a 

 small protuberance is observed rising in some weak part, which 

 increases until the substance of the pipe becoming thinner and 

 thinner, is at last rent asunder, when the pipe bursts with a crash, 

 and the water issues with great violence. 



In the first experiment, the pipe was of 1 1 inch bore, and the 

 metal, which was remarkably soft and ductile, one-fifth of an inch 

 in thickness. This sustained a power equivalent to that of a co- 

 lumn of water 1000 feet high, equal to 30 atmospheres, or 420 lbs. 

 per square inch of internal surface, without alteration ; but with 



