Some ^entarlis m tlje of 
Siinir Peasurenmit. 
By H. e. HELE SHAW, Assoc. M. Inst. O.E. 
rriHE various methods of Wind measuremeut, or Anemometiy, 
X cannot be profitably discussed without a clear under- 
standing of the objects for which the science is either useful or 
necessary, and these may be at once divided into two classes : 
1st. — The discovery of laws relating to the movement of the 
wind that may lead to reliable weather forecasts. This is 
a most important branch of Meteorology. 
2nd. — The knowledge of the action of the wind in its 
dynamical aspect, that is, of its force and velocity, in order to 
determine its effect upon structures or for purposes of navigation, 
and this is a nearly equally important branch of Engineering. 
With regard to the first of these objects, there is scarcely 
anyone who has not some knowledge of a subject to which so 
many eminent men have devoted their time, but though Sir 
John Herschel fifteen years ago bore testimony to the voluminous 
nature of the records and amount of work done, yet he held 
Meteorology, so far as weather predictions w^ere concerned, to be 
a science still in its infancy. That the wind does obey laws as 
certainly as any other body in nature, no scientific man for a 
moment doubts, and no better proof of this could be given than 
the regularity of the trade winds in latitudes comparatively 
free from disturbing causes, the action of which is completely 
accounted for on theoretic grounds, as also that of monsoons,. 
