The supply of water must be ample in dry weather.
In damp weather water must not drip from the wet bulb.
Water reservoir should be as far as possible from the dry bulb.
Dry bulb must never receive moisture from any source.
Use distilled, rain, or softest water procurable, for wet bulb.
When lime deposits from use of hard water change muslin and worsted.
Replenish reservoir after, or long before, taking an observation.
Well wash muslin and worsted before using.
Also wash occasionally while in use.
Change muslin twice a month or according to condition.