GB444274A - Improvements in or relating to instruments for indicating atmospheric conditions - Google Patents

Abstract

444,274. Hygrometric apparatus. WALLACE, A. S. J., 10, Rectory Drive, Gosforth, Northumberland. Nov. 29, 1934, No. 34365. [Class 97 (iii)] An indication of climatic or other ambient conditions determined by temperature and relative humidity is given in dependence upon the response of a thermometer and a hygrometric element of the type which changes its length with changes of humidity. In the form shown, the pointer 6 is moved over a temperature scale 7 by a bimetallic strip (not shown). A second pointer 9 is moved over a humidity scale 13 by a thread which is wound round the pointer spindle 8 and secured at one end to a tension spring and at the other to a hygrometric strip, e.g. of hair, paper, seaweed, catgut, artificial silk, or the material known under the Registered Trade Mark " Viscacelle." The area 14 in which the intersection of the pointers 6, 9 can occur is divided into sub-areas corresponding to the various climatic conditions. In a modification one pointer may be replaced by a drum and the other by a needle arranged to move across the drum. The instrument may be used to indicate the conditions in a coal mine or the state of the soil.