88 



NEGRETTI AND ZAMBEA, HOLBOEN VIADUCT, E.G., 



Tknmmttcr 



' 



being subtracted from resulting amount of water will give the value of the 

 collected snow or hail. 



" It is generally stated that a foot of snow gives an inch of water ; so that 

 one-twelfth of the depth of the snow in inches would be the amount of 

 rain corresponding to a given fall of snow. This estimate is, however, 

 only a very loose approximation, as the layer of snow is not always of uniform 

 density." 



| | 123. Bentley's Snow- Melting Bain 



Guage. (fig.102 .) A difficulty has hitherto 



\ S existed in the exact admeasurement of rainfall 



B3BBHHBEET IffiBHBHBH^ v ^ z -> ^' e necessity of leaving snow, sleet, or 



hail, whenever they occur, in the Gauge until 

 they can be melted ; the ordinary Gauge not 

 being always capable of containing the amount 

 of a long-continued fall of snow. 



This apparatus was contrived by Mr. R. 

 Bent-ley, at Upton (near Windsor), for use in 

 connection with an 8-inch Guage situated on 

 a roof inaccessible under ordinary circum- 

 stances. On reference to the accompanying 

 diagram, it will be seen that the distinguish- 

 ing feature of this Gauge is the melting of 

 any snow or sleet immediately on its reception. 

 This arrangement makes it very useful in 

 connection with any automatic registering 

 apparatus, or where the Gauge, from its posi- 

 tion, is not easily accessible, and at night. 



The action of the Gauge is briefly thus : 

 The rain or snow fall is received in the usual 

 8-inch funnel, from the bottom of which it falls 

 by gravity to the end of the tube (of whatever 

 length that may be) without touching the sides. 

 This is a very important point, and is gained 

 FIG 102. ky fitting a short guide-pipe, of some six inches 



in length, to the bottom of the funnel, and by the internal diameter of the long 

 tube being gradually slightly increased in proportion to the length of the tube. 

 At the bottom of the tube (which is within the house) is placed a tap and 

 measuring-glass. If preferred, the tap can be left open or removed, and an 

 automatic recording apparatus substituted. 



By the side of the main tube, but sufficiently distant from it for any heat 

 not to be conveyed sideways, is the melting tube. The hot air is furnished by 

 a gas jet or lamp or even a candle or night-light and being regulated to a 



