24 REPORT — 1844. 



numerically the effect of a given surface of air expanded by the rays of the sun. It 

 is easy to perceive, that to procure similar data from the daily sheets of Mr. Osier's 

 anemometer would require a very laborious as well as approximative calculation. 



The vane is double, similar to that of Mr. Osier. It is fixed to, and therefore 

 turns with, the perpendicular rod which pierces the ceiling, reaching within a few 

 feet of the ground, resting on the top of a cylinder of wood, round the circumference 

 of which are placed, level with the top, a series of thirty-two glass cylindrical tubes 

 of equal bore, the interstices being neatly filled up with putty or cement. 



Each tube represents a point of the compass, and they are intended to hold a co- 

 loured fluid, and are therefore sealed over at bottom, similar in fact to test tubes, 

 only considerably larger ; they are graduated so as to indicate the height of the liquid 

 within them, which height depends directly on the number of miles of wind which 

 has passed the vane in the twenty-four hours. Above the circle of tubes is an appa- 

 ratus which deposits the liquid into them ; there is also a contrivance, which is affixed 

 to the pressure plate, by means of which the fluid is deposited at a variable rate, but 

 always depending on the force on the pressure plate at the time. Thus, if for in- 

 stance a drop per minute answered to a wind of one mile per hour, two drops per 

 minute would show a velocity of two miles per hour, fifty drops a minute a velocity 

 of fifty miles ati hour, and so on ; and as the tubes collect the daily deposit, by 

 simply reading off the daily deposit or elevation of the fluid, and noting the respec- 

 tive tube or tubes in which it is found, we have at once the number of miles of air 

 which has passed the station as well as the direction. 



To describe the apparatus by which the quantity of fluid is regulated, so as to flow 

 in proportion to the wind's velocity, would require a diagram ; but the general cha- 

 racter is sufficiently obvious to give the meteorologist a good idea of it. Mr. Osier's 

 clock is superseded by clepsydral arrangements, and the spiral spring for the pressure 

 plate is replaced by the natural spring of water, which is far superior to any artificial 

 spring. In concluding, the author urges on the Members of the Association the im- 

 portance of instituting experiments, to be made with a view of correcting our constants 

 relating to the velocity of wind appertaining to a given force, as the errors of the tables 

 will much interfere with extensive computations. 



On an Instrument called a Barometer Pump, for filing Barometer Tubes in 

 vacuo. By Lieut.-Col. Everest, F.R.S. 



This was a single acting air-pump, so arranged as to exhaust the air from the tube 

 to be filled, while a capillary tube, dipping into a reservoir of mercury, and curved at 

 the end next the tube, dropped the mercury into the tube as it rose above the bend 

 (after the exhaustion had been carried as far as possible), by dipping a glass rod into 

 the reservoir. The mercury as it comes into the tube is heated to a temperature 

 sufficient to boil it, and it is desiccated by a bottle of strong sulphuric acid, which is 

 made to communicate with the canal into which the tube to be filled and the capillary 

 filling tube are luted. Col. Everest mentioned, that the best material for the valves 

 of an air-pump was the swimming bladder of a fish. 



Account of an Attempt to establish the Plastic Nature of Glacier Ice by direct 

 Experiment. By Professor J. D. Forbes, F.R.S. L. Sf E. 



These experiments were made in the month of August last upon the Mer de Glace 

 of Chamouni, with the view of establishing that the increasing velocity of a glacier, 

 from the side towards the centre, takes place (when the declivity is not very great) 

 by the insensible yielding of one portion of the ice past another, without great rents 

 at measurable distances producing discontinuity in the motion. The only permanent 

 marks left by such differential motion are the veins, or blue-bands, to which the 

 author has, in his published writings, attributed such an origin. 



A transverse line was drawn partly across the glacier in the most compact part 

 which could be found, which was quite devoid of open crevices for a considerable 

 space. The theodolite was planted over a fixed mark in the ice at the extremity of this 

 line nearest to the lateral moraine of the glacier ; and the relative, or differential 

 velocities of the parts towards the centre were determined at short intervals, and have 



