Hygrometer, Wet & Dry Bulb, Mason’S

Comprising Two Thermometer Tubes With Double Scale Graduation, Mounted On A Weather-Proof Case With Shade. Dual Scales Graduated -10 To 50 x 1°C And 20 To 120 x 2°F. One Thermometer Kept Dry And Other Has Bulb Covered With Muslin Or Wick, Dipped Into A Water Reservoir, Which Keeps It Wet During Long Periods Of Non-Use. Comparing The Reading Of Wet And Dry Thermometer With The Humidity And Temperature Conversion Chart Included, Relative Humidity Can Be Worked Out. (Mounted On Plastic Base)