Dew-point hygrometer

Claim 1

IN A DEW-POINT HYGROMETER, IN COMBINATION, A DEWFORMING ELEMENT HAVING ELECTRICAL MEANS FOR MODIFYING THE TEMPERATURE THEREOF, SAID TEMPERATURE-MODIFYING MEANS HAVING A CONTROL CIRCUIT FOR ADJUSTING THE OPERATION THEREOF IN ACCORDANCE WITH THE ELECTRICAL CONDITION OF THE CIRCUIT, PHOTOELECTRIC MEANS OBSERVING THE ELEMENT, FOR PRODUCING A SIGNAL OUTPUT WHICH DEPARTS FROM ZERO IN ONE DIRECTION OR THE OTHER IN ACCORDANCE WITH PRESENCE ON THE ELEMENT OF MORE OR LESS THAN A PREDETERMINED AMOUNT OF DEW, ELECTRICAL MEANS CONTROL BY THE PHOTOELECTRIC MEANS AND VARYING THE ELECTRICAL CONDITION OF SAID CONTROL CIRCUIT IN IMMEDIATE RESPONSE TO CHANGE IN THE OUTPUT OF THE PHOTOELECTRIC MEANS DUE TO CHANGE IN DEW CONDITION OF THE ELEMENT, FOR ADJUSTING THE TEMPERATURE-MODIFYING MEANS TO MAINTAIN THE TEMPERATURE OF THE ELEMENT IN EQUILIBRIUM AGAINST CONTINUANCE OF CHANGE IN DEW CONDITION OF SAID ELEMENT, SAID TEMPERATURE-MODIFYING MEANS BEING ADAPTED TO REQUIRE DIFFERENT ELECTRICAL CONDITIONS IN THE CONTROL CIRCUIT TO INTERRUPT CHANGE IN DEW QUANTITY AT DIFFERENT TEMPERATURES OF THE ELEMENT, SO THAT SAID ELECTRICAL MEANS TENDS TO PRODUCE SAID EQUILIBRIUM AT SOME TEMPERATURES WITH A NON-ZERO SIGNAL REPRESENTING CONTINUING DEPARTURE OF THE DEW QUANTITY FROM SAID PREDETERMINED AMOUNT, A SUPPLEMENTAL ELECTRICAL SOURCE CONNECTED TO SAID CONTROL CIRCUIT, AND SUPPLEMENTAL MEANS ELECTRICALLY CONTROLLED BY THE PHOTOELECTRIC MEANS AND ADJUSTING SAID SUPPLEMENTAL SOURCE IN SLOWER BUT CONTINUOUS RESPONSE TO DEPARTURE OF THE OUTPUT OF THE PHOTOELECTRIC MEANS FROM ZERO SIGNAL, FOR SUPPLEMENTARILY VARYING THE ELECTRICAL CONDITION OF THE CONTROL CIRCUIT SO THAT THE TEMPERATUREMODIFYING MEANS MAINTAINS EQUILIBRIUM OF THE TEMPERATURE OF THE ELEMENT AT THE ZERO SIGNAL POINT PROVIDING THE AFORESAID PREDETERMINED AMOUNT OF DEW.