"W. MARRIOTT — ITETEOROLOGICAl OBSERVATIONS. 



215 



Rain-gauge. — The Rain-gauge should be made of copper, and 

 have a funuel of five or eight inches diameter. It is very desir- 

 able that it have also a deep rim. It should be set in an open 

 and well-exposed situation, entirely free from trees, walls, and 

 buildings. It must be firmly fixed so that it cannot be blown 

 over ; the top of the funnel should be one foot above the ground and 

 must be quite level. The measurement of the rain simply consists 

 in pouring out the contents of the bottle or can into the glass 

 measure, which must be held quite vertically, and reading off 

 the di\asion to which the water rises. The amount should always 

 be written down before the water is thrown away. The gauge 

 must be emptied every morning at 9 a.m., and the rain-fall entered 

 to the previous day. If it is known that no rain has falh n, the 

 gauge should, nevertheless, be examined, and a line or dash in- 

 serted in the register. It is desirable that very heavy faUs 

 of rain should be measured on their termination, and the par- 

 ticulars entered in the remarks ; but if this be done, the water 

 should be returned to the gauge, so that the next ordinary regis- 

 tration may not be interfered with. When snow falls, that which 

 is collected in the funnel is to be melted and measured as rain. 

 It is also desirable to measure with a rule the depth of snow in a 

 place where it has not drifted, and enter it in the remarks. 



Wind. — The direction and force of the wind may be ascertained 

 by estimation, or from a vane and anemometer, where such are 

 available. It is absolutely necessary to first obtain and mark a 

 fixed point of the compass — jS". is the best ; this may be done by 

 observing Polaris, the ]S^orth Star, on a clear night, or noting the 

 shadow of a building, etc., when the sun is due S. about noon. 

 The direction of the wind is that point of the compass /row which 

 it is blowing. Care must be taken that the direction is that of the 

 general current of air passing over the place, and that it is not 

 locally aff'ected. The wind is influenced by so many local causes, 

 that anemometers, unless they are very well exposed, can hardly 

 ever record its true direction and force. The direction can be 

 obtained by observing the drift of smoke from tall chimneys or low 

 clouds. The force is generally obtained by estimation, the scale 

 employed being the following : — 



If a Robinson's cup anemometer be used, it must be mounted on 

 a pole in a freely-exposed situation, so as to be quite uninfluenced 

 by buildings, trees, etc. 



Clouds. — The proportion of sky covered with cloud must be ob- 

 served. This is done by estimation, the scale adopted being to 

 10, — representing a cloudless sky, and 10 a completely covered 



