Dr Fleming on a Simple Form of Bain-Gauge. 185 



Fig. 1 is the external cy- 

 linder, closed at bottom, and 

 sunk perpendicularly into the 

 ground, with its margin on a j^-^^ 

 level \vith the earthy surface, f^hi^^^ 

 Fig, 2 is the inner cylinder or '^■»>^'^i''^>^ 



mm 



mil 



ii 



'5^ 



mi 



rain-gauge, open at top, to act 

 as a funnel for receiving the 

 rain, but closed at the bottom, 

 except the central stop-cock, 

 fig. 3, for letting off the water. 

 This inner cylinder or gauge, 

 is no narrower than its case, 

 unless in so far as to allow of 

 its being easily lifted out for 

 the purposes of adjustment. 

 This inner cylinder is fur- 

 nished with a shoulder or 

 flange, fig. 4, to close upon the mouth of the case, and prevent 

 the entrance of any earth, sand, or leaves, so as to obstruct 

 the easy elevation of the gauge. 



Fig. 5 is the surface of the grass plot in which the gauge 

 is placed, and which must be kept in a trim condition in its 

 immediate neighbourhood. 



Fig. 6 is the hollow float to which the index-rod 7 is at- 

 tached. The rain which falls into the mouth of the cylinder 

 will be conducted by the funnel, fig. 8, situate an inch and a 

 half within the margin (to which it is soldered) into the re- 

 ceiver, fig. 2, and raise the float to a corresponding degree. 



Fig. 9 is a thin vertical sti'ip extending across the middle 

 of the mouth, with a sheath at the centre to embrace the rod, 

 as a guide, and to serve as determining the zero of the scale 

 and the indications of change. When the stopcock, fig. 3, 

 has been open, and the water let off^, the beginning of the 

 scale on fig. 10 will usually be a little lower than the mark- 

 ing edge, fig. 9. In this case, a little water is poured into 

 the cylinder, in order to bring the commencement of the scale 

 to zero, or fig. 10, and, on the falling of rain, the index rises, 

 and, being divided into inches and tenths, numbered down- 

 wards on the rod, the quantity is readily seen by inspection. 



