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In my first investigations, as already mentioned, I employed 

 a square frame for the limitation of the surface-unit, 1 ko square 

 metre in extent. On journeys, and on long excursions which have 

 other objects in view besides formation-investigation, such a frame 

 is, however, rather impracticable, among other reasons because of 

 the difficulty of transport; in addition, it is impracticable in the 

 investigation of certain formations, especially Nanophanerophytic 

 formations, as for instance Macchi, as the frame when thrown is 

 easily caught in the branches of the plants and sometimes in places 

 which are perhaps difficult of access owing to the plants being 

 thorny. On my visit to the countries of the Mediterranean in 

 1909 — 10 I did not therefore employ a square but a circle for the 

 limitation of the samples, having fastened to my stick a thin metal 

 rod the length of which was equal to the radius of a circle in- 

 cluding surface-measure of Vio square metre. This method proved 

 to be very practicable and afterwards I always employed it at my 

 investigations. Here, I shall give a short description of the simple 

 apparatus which I employed. 



The apparatus consists of a ring, formed of two halves con- 

 nected by a hinge, which by means of a screw (see Fig.) can be 

 fixed on a walking 

 stick at a height suit- 

 able to the occasion; 

 a piece of metal is 

 fixed into one side 

 of the ring; its free 

 end has on the inner 

 surface a screw-thread 

 into which a metal rod 

 can be screwed; as 

 regards the length of this rod, when it is screwed entirely in, then 

 the distance between the median line of the stick and the free end 

 of the rod is equal to the radius of a circle including the surface- 

 measure employed as unit, in the present case 1 /io square metre. 



The mode of proceeding at the investigation of any particular 

 formation is as follows: with stated intermediate spaces — for in- 

 stance at every fifth step or whatever distance is considered most 

 suited to that particular case — the stick, which has an alpenstock- 

 ferrule, is stuck into the ground, and every species which occurs 

 within the circle described by the tip of the rod fastened to the 



