38 REPORT — 1856. 



and progressive motions of Atlantic cyclones, given by Redfield, Reid, &c. M. Liais 

 having favoured me with an opportunity of studying his unpublished charts of the 

 Balaklava tempest, I have found therein a distinct and impressive confirmation of 

 the correctness of the method of interpreting barometric fluctuations according to the 

 laws of cyclonology. These charts fully establish the truth of the inferences derived 

 above from the contemporaneous barometric curves in Britian. They prove that the 

 Balaklava tempest was a cyclone, moving to the eastward, along a central track which 

 lay to the southward of Britain. It is known that during their transit from the 

 Gulf of Mexico to the western coasts of Europe, across the comparatively uniform 

 surface of the ocean, cyclones preserve an approximately circular form. The excellent 

 charts of M. Liais, at the same time that they exhibit the progress of the storm day 

 by day, from the shores of Britain across the continent of Europe, to the Caucasian 

 mountains and the borders of the Caspian Sea, show also the remarkable modifica- 

 tions produced in the normal condition of the cyclone by mountains and other 

 irregularities of the surface of the land. Thus, for example, a portion of the cyclone 

 is delayed nearly twenty-four hours in passing the Alps. The consequence of this 

 and similar obstructions is, that what was nearly a circular atmospheric wave while 

 crossing the ocean, takes the form of a much elongated and somewhat distorted 

 ellipse on land, enveloping an elliptical central area of maximum barometric depres- 

 sion, which extends, on one chart, from Dantzic in the Baltic to Varna in the Black 

 Sea. Around this central space the wind still blows continuously in the direction 

 peculiar to the cyclones of the northern hemisphere. In the case therefore of the 

 Balaklava temjiest, whose nature has been determined with much greater exactness 

 than that of any other tempest on land, we have unequivocal testimony that the 

 principles of cyclonology may be safely applied to interpret the fluctuations of the 

 barometer in Great Britain. 



On a Model of a Self- Registering Anemometer. Desig?ied and Constructed by 

 R. Beckley, of Kew Observatory. Described by Mr. Welsh. 



In this model Mr. Beckley has adopted Dr. Robinson's method of measuring the 

 velocity of the wind by the rotation of a system of hemispherical cups, the direc- 

 tion being indicated by a double wheel-fan like the directing vane at the back of a 

 windmill. A stout tubular support carries the whole of the external part of the 

 instrument, including the measurer of velocity, the direction vane, and a rain-gauge. 

 This support is so made that it can be easily adapted to the roof of any building 

 upon which it may be necessary to mount it. All the rotatory parts of the anemo- 

 meter run upon friction balls. The shaft of the apparatus for measuring the move- 

 ment of the wind, by means of a diminishing train of wheels, is made to turn a 

 cylinder upon which is wrapped a sheet of paper of the kind used for "metallic 

 memorandum books," this paper having the property of receiving a trace from a 

 style of brass. The sheet of paper is divided into two sections, upon one of which 

 is recorded the motion of the wind and upon the other the direction. As the 

 cylinder is being turned by the action of the wind, a clock carries a pencil along the 

 cylinder at a uniform rate of 1 2 inches in the twenty-four hours. To the lower end of 

 the direction shaft is attached a spiral of such a figure that equal angles correspond to 

 equal increments of radius; the edge of this spiral consists of a thin slip of brass, which 

 touches the paper and records the direction of the wind on a rectilinear scale. When 

 the sheet of paper is unwrapped from the cylinder after twenty-four hours, the motion 

 of the wind and the direction are both found projected in rectangular co-ordinates. 



With reference to anemometric observations at sea, Mr. Welsh read the following 

 extract from a letter which he had addressed to the Chairman of the Kew Committee, 

 describing a method of making allowance for the efl^ect of the ship's motion upon 

 the observed velocity and direction of the wind : — ^"By means of a portable Robinson's 

 anemometer, provided with a means of observing the total number of turns made by 

 the rotating part in any given lime, observe the apparent velocity of the wind and 

 record it in knots per hour. By an anemoscope of any kind register the apparent direc- 

 tion of the wind. From the log-book take the rate and direction of the ship's motion. 

 On a slate or other similar surface scratch a permanent compass circle. Set off from 

 the centre of the circle, on the radius of the direction of the ship's head, by any 



