How to Test a Hygrometer. If you're a cigar aficionado, you need a hygrometer to make sure you're storing your wares at the correct humidity. A hygrometer is an instrument that is used to measure humidity in cigar humidors as well as greenhouses, incubators, museums, and more.
verb (used with object), inferred, inferring. 1. to derive by reasoning; conclude or judge from premises or evidence: They inferred his displeasure from his cool tone of voice. 2. (of facts, circumstances, statements, etc.) to indicate or involve as a conclusion; lead to. 3. to guess; speculate; surmise.
Learner's definition of ASCERTAIN. [+ object] formal. : to learn or find out (something, such as information or the truth) They were unable to ascertain [=(more commonly) determine] the cause of the fire. The police are now attempting to ascertain his whereabouts. [=to find out where he is] Her doctors have been unable to ascertain [=find out] why she is ill. = Her doctors have been unable to ascertain the cause of her illness.