TRANSACTIONS OP THE SECTIONS. 20f 



given every satisfaction. It has not required any repairs, gives no trouble, and is in 

 as good working condition as when it was set to work in 1853. For details see the 

 • Civil Engineer and Architect's Journal,' October 1855. 



On a Pressure Water-Meier. By William Gorman. 



This water-meter contains a vane-wheel, driven round by the water to be measured, 

 which is supplied at the periphery of the wheel and withdrawn at the centre ; the 

 principle of action being the same as in the engine above described. The openings 

 for the supply of the water are regulated by self-acting loaded valves, which con- 

 tract these orifices when the flow is small, and prevent the stream from becoming too 

 feeble to move the vane-wheel. The revolutions of the vane-wheel are registered by 

 a train of wheel-works*. 



This meter has been in use in various works in Glasgow since 1 852, and has given 

 ample satisfaction. It is not subject to derangement ; and should it require adjust- 

 ment or repair, it can be taken away without interfering with the water supply. For 

 details see ' Civil Engineer and Architect's Journal/ October 1855. 



On the MeoMirement of Ships. By Andrew Henderson, CE. 



On Working a Steam-engine loith Rarejied Air. By M. Holden. 



Mr. Holden described an experiment made under his observation in 1809, which 

 showed the applicability of rarefied air to an engine instead of steam. 



On a Compass independent of Local Attraction. 

 By Robert Jamieson, C.E. 



On a new Air-Pump exhibited by James Laing. 



The principal pecuharity was dispensing with the valve, two pistons being placed 

 in one cylinder, so as to act as valves to each other. 



1^ 



On the Structure of Shell Mortars without Touch-hole, to be discharged by 

 Galvanic Circuit. By Professor Macdonald. 



« the Metra. By Herbert Mackworth, Government Inspector of 

 Mines, M.Inst. C.E ., F.G.S. 



The instrument called " Metra," from its including a variety of measures, is in- 

 tended for the common use of mining and other engineers, for geologists, scientific 

 travellers, &c. The portability of the instrument will induce the taking of more 

 scientific observations by such persons. A brass box, 2| inches square and 1 J inch 

 thick, throws open at top and bottom, fastening out by a screw so as to form a 

 measuring side 5| inches long. 



By placing the clinonometer level at zero, and laying the side of the instrument 

 on the rock, the strike or level course of a bed of rock may be at once found and 

 read otf on the compass, which is made as large as possible. The bottom of the 

 compass being made of glass, the strike of the roof of a mine can be, in like manner, 

 found, and then read off from the under side of the card. The amount of inclination 

 in degrees or in inches of fall per yard, is found by the level. In the above cases 

 the accuracy of reading is to a°. The level course or inclination of long lines can be 

 found by the two sights. For taking the direction of highly inclined lines, one of 

 these sights turns down, and the plummet is suspended to a screw at the other end of 

 the instrument. A brass surveying leg, with adjusting joints, fits into a socket on 



* This engine is still in good order, working regularly, and has not required any repairs 

 12th May, 1856.— Wm. Gorman. ' 



