220 REPORT— 1876. 



which the links of the marine engine are attached. In this way these links follow 

 the motion of the reversing lever, and are locked fast at any degree of expansion 

 in the quadrant. 



On a MacJiine for the Liquefaction of Gases hy combined Cold and Pressure. 



By J. J. Coleman, F.C.S. 



This paper describes a powerful machine, erected for dealing with 300,000 feet 

 per day of waste gases at the works of Young's Paraffin Light and Mineral Oil 

 Company. 



The machine includes — 



1st. The pumping of the gas by steam-power into a system of tubes externally 

 cooled by water, and from which condensed liquids ai*e withdrawn. 



2nd. Employing the condensed gas, after being deprived of liquids, for working 

 a second engine coupled with and parallel to the first, thus recovering a portion of 

 the force originally employed in compression. 



.'jrd. Employing the expanded gas, having had its temperature reduced in the 

 act of doing work, as a cooling agent for a portion of the condensers to near zero 

 Fahrenheit. 



On Drainage Outlets through Shb Lands. By A. CRUM:-E■^^■ING. 



The author described the means he had emploj-ed to open up a channel two 

 miles long through slob, in the colony of Demerara, for the purpose of reestablish- 

 ing natural drainage. This slob is a deposit from the gi'eat rivers of the northern 

 part of South America ; and when it sets in in front of the plantations, completely 

 blocks up their drainage outlets. The method employed was to lay a steel rope 

 all the length of the mud-bank, and, by means of Fowler's clip-drum placed in a 

 small steam-vessel, which had strong drag-harrows attached, to run the whole 

 apparatus rapidly from end to end of the rope. When the water discharged from 

 two very powerful centrifugal pumps was brought to bear after the dredge, a 

 marked effect was produced, and a channel was being rapidly opened deep enough 

 and wide enough to carry off the heavy rainfalls (sometimes as much as six inches 

 in twenty-four hours) without having recourse to pumping — a matter of gi-eat con- 

 sequence, as the expense and risk of pumping are large. 



On recent Attempts at Patent Legislation. By St. J. Vincent Day. 



On the For^n of Blocks for Testing Cement. By G. F. Deacon. 



On the Strength of Concrete as affected by delay between mixing and 

 ■placing in situ. By G. F. Deacon. 



Description of Stobcross Docls. By J. Deas. 



The first portion of ground purchased for the works was in 1845, and consisted 

 of 36 acres. At that time a wet dock and tidal basin were proposed, having a 

 total water space of 17 acres and IG acres of quay space, the length of quayage 

 being 1458 yards. Until within the last few years, however, the Clyde trustees 

 were able to obtain ground on both margins of the river sufficient for the required 

 quay extension, the river itself forming the water space, and requiring little ex- 

 pense to make it available opposite the new quays. 



In 1864 the Edinburgh and Glasgow Railway Company (now merged in the 

 North British Railway Company) obtained an act to make a railway from their 

 Helensburgh branch to the authorized docks, with a station immediately on the 



