Transpirograph 



FOR 



Demonstration 

 and Research 



To record the rate of trans- 

 piration the plant is placed on 

 a balanced scale-pan. As it 

 loses water it is raised, touch- 

 ing a release which closes an 

 electric circuit. An electro- 

 magnet then releases a 1-gram 

 ball weight (200 of which are 

 carried in a tube) which drops 

 into the scale-pan. The bal- 

 ance is restored and the pro- 

 cess repeated. 



Each 1-gram loss is recorded 

 on a drum driven by clock- 

 work. It is possible to read 

 directly from the record the 

 number of minutes required 

 for the plant to lose one gram 

 of water. The apparatus pro- 

 vides for a continuous record 

 of seven days duration, one 

 adjustment per day being re- 

 quired. 



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 Apparatus 



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