A Hijgrothermograph Puzzle 



281 



A HYGROTHERMOGRAPH PUZZLE. 



W. H. Larrimer, U. S. Entomological Laboratory, Lafayette, Indiana. 



In the course of the investigation of some biological problems it 

 is frequently desirable to secure temperature and humidity records for 

 possible correlation with the behavior of the individuals under observa- 

 tion. At a one man observation station it sometimes happens that the 

 attendant's services are badly needed elsewhere on the particular day, 

 usually Monday, when the record sheets of recording instruments are 

 to be changed. In order to take advantage of such occasions and at 

 the same time have the records continue uninterruptedly, a scheme was 



Fi«'. 1. riyKiothenno.aiaiih showing the lecorcUriL;' liens in position as they jiass 

 fionj the old to the new lecord sheet without interiuption of records. 



originated by which the attendant could put on the new record sheet 

 before his departure and so arrange it that the graph would continue 

 from the old to the new sheet on Monday without further attention. 



On the day of departure the clock is wound and a new record sheet 

 is placed in position in the usual manner. Most of the used portion 

 of the old sheet is folded under so that the new sheet is left exposed 

 until the same day of the following week. The edge of the unused 

 portion of the old sheet is folded snugly under and arranged so that 

 the respective time arcs and horizontal percentage or degree lines are 

 coincident with those of the new sheet. (See Fig. 1.) 



The bar which usually is furnished to hold the record sheet in 

 place can very well be replaced by strong elastic bands at the top 



"Proc. 38th Meeting, 1922 (1923)." 



