V. RAIN GAUGES. 581 



An instrument constructed at the Kew Observatory, in 1843, by Mr. Francis 

 Ronalds, for indicating a mean result from the quantity of water which may 

 have fallen between any two given periods, minus the quantity of vapour 

 which has evaporated in the same time, on and from a circular plane of one 

 foot diameter. It is described in the British Association Report for 1844. 



It consists of two cylindrical vessels, connected by a tube, the one being 

 one foot in diameter, and open at the top, whilst the other is inches, and 

 (with the exception of a small hole) entirely closed by a cover, which car- 

 ries a frame, holding a circular divided arc, with an index moving over it. 

 The index is attached to a small pulley, over which a cord passes, having 

 its end fixed to the float in the cylinder. This, rising and falling with 

 the changes of water level, indicates the amount of rain or evaporation on the 

 metal scale. 



2852. Glaisher's Rain Gauge. Francis Pastorelli. 



This instrument has a greater internal depth, the coned part being 3 inches 

 from the surface ; in this respect it more resembles the Admiralty pattern ; it 

 prevents heavy rain splashing over, and consequent loss. 



2852a. Mountain Bain Gauge. Capacity 48 inches. Pat- 

 tern employed in the English lake district and at very wet moun- 

 tain stations in Wales and Scotland. G. J. Symons. 



2852b. Engineer's Bain Gauge. Capacity 12 inches. 

 Adapted for rough observations in ordinary hilly districts. 



G. J. Symons. 



2852c. Glaisher's 8-inch Bain Gauge. Adapted for and 

 largely used by private observers. G. J. Symons. 



2852d. Snowdon Pattern Bain Gauge, originally designed 

 for use in North Wales, the deep cylinder being added to secure 

 better observations during snow. This gauge is now in general 

 use in all parts of the British Isles. G. J. Symons. 



2852e. Indestructible Monthly Bain Gauge for private 

 observers. G. J. Symons. 



3852f. Copper Bain Gauge, Glaisher's form. 



E. Cetti and Co. 



2852g. Electrical Self-registering Bain-gauge. 



Yeates fy Sons. 



The peculiarity of the above is a novel form of rocking bucket, the parti- 

 tion of which is so constructed that it will register correctly, no matter at 

 what rate the rain may fall. 



2852h, Self-registering Bain Gauge. Elliott Brothers. 



This instrument consists of an upright square metal case, with funnel or 

 receiver 10 inches square, with a set of counting wheels with dials registering 

 from -^-^g. to 100 inches of rain fallen. The water falls into a trough with 

 a division in the centre, having a motion on an axis, and being put at an angle, 

 the rain overbalances it alternately, and is registered by the motion being 

 communicated to the set of wheels, and consequently there is no evaporation 

 to be deducted. 



