38 



Selim Lbmstböm. 



The observations résultée! in the following table: 



TAB. III 

 Jime IStii 1880. 



The tlierinometers placed at points c, f, g and li being partly surrounded 

 by smoke, their indications are not included in the resuit. Point d was also 

 once under a layer of smoke, wliicli made the température rise to — 1,7, but 

 directly afterwards it feil to — 3,5. As the torches were lighted that evening 

 as early as 10 p. m., the observation at 10, i5 p. m. is included in the cal- 

 culation of the avei'age number. 



This is, in the lower thermometers in the field 



+ 0»,Ü7, 



and in d (T„) 



2",.3 



or a différence of température of 



3",o. 



The greatest différence between the average température in the field and 

 that outside the field, is 3",5, and the least 2-,2. 

 • A greater différence occurs at 1. p. m. in a and d, being 3",9. 



It is to be observed that during this experiment a gentle breeze froiu the 

 E prevailed ail the time, carrying away both smoke and vapour, so that the 

 expérimental field was covered with only a thin layer of smoke. The changes 



