In higher latitudes night-frosts frequently occur during the time of vegetation. 

 The frost is often strong enough to destroy vegetahles, to the great détriment 

 of agriculturists, and such a cahiraity often happens over extensive tracts 

 followed by famine and all its fearful conséquences. Finland suiïers from it 

 several times during every century. Great disturbances in all the private 

 affairs and relations make tliis phenomenon and its conséquences a miglity 

 factor in the economy of the whole country. No wonder that many men of 

 science have consecrated much work on the researches of its causes. ïo- 

 wards the end of last century P. A. Gadd wrote a good essay on this matter, 

 but it was tirst in G. G. Hällströms work on the night-frost, that a really 

 scientific investigation of it was made. Hällströms work appeared in 1807 and 

 consequently before the discovery of radiant heat and its laws, hence it does 

 not deal witli the nearest causes of night-frost, hut with the more remote ones, 

 and thus principally with them making a place susceptible to frost. This valuable 

 work contains also good information for every agriculturist who wants to les- 

 sen the danger of frost by useful préventive means. 



The destructive influence of night-frost and the desolate aspect of a ruined 

 corn-field have caused me to continue the study of the phenomenon in order to 

 penetrate its nature. 



Observations and calculations led to the conclusion that the possibility of 

 preventing the damage by frost not only exists but also that a protection against 

 it could be executed in a comparatively simple manner. Ätter having 

 cleared this matter, a series of preparatory experiments was made, partly at 

 the expense of Governor T. Costiander, owner of Notsjö, in Urdiala. I was 

 soon convinced that only experiments on an extensive scale could give results 

 generally satisfactory, but the expense became thus too great for private means 

 and I was obliged to make application to the Finnish Government. Thi'ough 



