May 25, 1888.] 



SCIENTIFIC NEW^S. 



SIMPLE METEOROLOGICAL INSTRU- 

 MENTS. 



MR. RUSSELL, of New South Wales, the well- 

 known astronomer, has devised a very simple 

 form of self-recording anemometer, intended for use in 

 country stations in Australia. Our illustration gives a 

 general view of the apparatus. The cups are four inches 

 in diameter, and four feet apart from centre to centre, 

 and they drive a spindle carrying a toothed wheel, which 

 in its turn drives another wheel on a horizontal axis. 

 These wheels are contained in the square box at the top 

 of the pole; the rim of the horizontal wheel is grooved. 



Anemometer and Evaporator at the Sydney 

 Observatory. 



An endless wire, kept taut by a weight and pulley in 

 the chamber at the bottom of the apparatus, passes one- 

 and-a-half times round this groove, so that, as the vanes 

 revolve the wire is slowly drawn up. Attached to the 

 lower part of the wire is a carriage which holds the 

 recording pencil, and presses it against a drum driven 

 by clock work. When the carriage reaches the 

 top of the cylinder it must be detached and again placed 

 in position at the bottom, but this only occupies a few 

 seconds. 



In front of the anemometer Mr. Russell's apparatus 

 for measuring evaporation is shown. It consists of a 

 galvanised iron tank measuring four feet in diameter and 

 three feet in depth. This is sunk into the ground to the 



depth of two feet eleven inches, the inch projecting above 

 the ground being left to prevent surface water finding its 

 way into the vessel. Grass is grown round it, flush with 

 the top, for the double purpose of keeping rain from 

 splashing in, and of preventing the sun's rays from 

 warming the outside of the vessel. A light vertical rod, 

 working in guides, is attached to a float, and the amount 

 of evaporation is read off on a scale fixed close to it. 



■^^>t^>^5tf-» . 



WATER-SPOUTS AND WHIRL- 

 WINDS. 



ASOI^IEWHAT prolonged controversy has taken place 

 at the Academy of Sciences between M. Faye and 

 M. Colladon. The former savant declares that he has 

 observed in fluids merely descending rotatory movements. 



M. Colladon's Apparatus for Showing Ascending 

 Rotary Movements in Fluids. 



M. Colladon maintains that ascending movements occur, 

 and has devised the following experiment to show that 

 such is the case. Into a glass vessel about two feet high, 

 and nearly filled with water, is fixed a wheel, provided 

 with small floats, attached to a vertical axis, which can 

 be rotated at high speed by means of toothed gearing. At 

 the bottom of the vessel is placed some coarse saw-dust 

 previously boiled in water to expel the air. If the wheel 

 be rotated at a speed of four to five turns per second the 

 saw-dust is drawn up in a spiral, and our illustration is 

 reproduced trom a photograph taken just as the wood 

 particles reached the wheel. But if we continue to turn 

 at the same rate the water-spout becomes cylindrical, or 

 nearly so. 



li we turn much more swiftly the air descends some- 

 times to the wheel, and we have two spouts, one ascend- 

 ing and the other descending, which struggle and cross 



