30 Selim Lemström. 



is put to a little more than its leiigth into the sloping mud-tube and tlien 

 kindled. At first it burns in a flame but soon begins to produce so much heat, 

 that the mud-tube begins to carniboze. The torch thus constructed can be ma- 

 nufactured at a price of 3 or 4 pennis and possesses, in a high degree, all 

 the above mentioned qualities of the combustible. 



IV. 

 EXPERIMENTS IN THE FIELDS. 



In order to ascertain Avhat number of torches ought to be applied to a 

 certain area, a series of experiments has been made at Notsjö in the parish 

 of Urdiala in SW Finland dming the month of June 1880. 



The fleld, where the experiments were made, consisted of recently culti- 

 vated ground, partly meadow, partly bog, and was situated 4 km from the 

 premises. The map here attached will give an idea of its condition and boun- 

 daries. The situation of the ground is very low and bounded on the S by 

 marshy boglands, and on the SW and W by low meadow-ground, on the N 

 by woods sloping gently towards the field, on the E by low meadows. Along 

 the S side of the fleld a sand-hill, intersected by a valley, runs westward. 

 On the other side of this sand-hill was a boggy morass, partly wooded and sho- 

 mng signs of an attempt at cultivation. A stream, formed by two ditches 

 uniting in the middle of the field, runs through the ground, which slopes gently 

 from both sides towards this stream. About the middle of the field, a little 

 farther northward, there is a wooded hill, on which there stands a kiln for 

 drying grain; near the junction of the trenches there is a barn. To the NW 

 there is some cultivated land. 



EXPERIMENT I. 



June 11»'' 1880. 



Judging from the foreboding signs, a night-frost, in the proper sense of 

 the word, was not to be expected, especially as the température at 8. p. m. 

 was still + 13",o, but already at 10,i5 p. m., or about an hour after sun- 

 set, the temperatiu-e had gone down to — 2",3, in a place C, in the fleld near 



