86 



NEGEETTI AND ZAMBRA, HOLBOEN VIADUCT, E.G., 



-80 



r-30 



E-io 



TIG. 99. 



FIG. 



119. Negretti and Zambra's Tropical Rain Gauge, similar in form to 

 No. 99, but of extra large size, to hold 50 inches of rain, with a metal tap for 

 drawing off the collected water. 



Price, complete with receiving vessel and graduated measuring 



jar in japanned metal 2 10 



Ditto Ditto in Stout Copper . . . .350 



120. Crossley's Registering Rain Gauge (fig. 100.) is a 10-inch square 

 guage, the receiving area being equal to 100 superficial inches. The water col- 

 lected by the funnel passes down a tube to a vibrating bucket connected with 

 and giving movement to a train of wheels communicating with three dials 

 recording the amount of rain passing through the gauge, in inches, tenths, and 

 hundredths. The mechanism is simple, and if occasionally examined and 

 kept clean it will give a faithful record to -^-th of an inch depth of rain. A 

 small test measure, holding 5 cubic inches of water, is sent with each instru- 

 ment for the purpose of testing and correcting the gauge, and full printed 

 instructions for fixing, reading off the dials, &c., &c., accompany each 

 instrument. Under careful management this registering gauge will be found 

 very useful. Price, 4 12 



Great care should be taken to prevent the edge of the collecting or 

 receiving funnels of Rain Gauges being bent or dented, for should the area be 

 not a true circle the full amount of rain will not be collected. Circular Rain 

 Gauges are preferred to Square ones, the latter being more liable to get out of 

 shape than the former. 



