436 



same transverse line ; they are placed two and two in lines 

 obliquely to the longitudinal direction of the keel (with one 

 single exception), the advantage of which arrangement is that 

 the friction which the edges of the nail-ends must produce, as 

 the, sledge glides over the snow, is evenly distributed, being alter- 

 nating and in no transverse line produced by more than one nail- 

 end a.t a time. At the same time the holes form two long rows, 

 which extend almost parallel to each other from one corner of 

 the rhomboidal figure formed by the outline of the keel tow- 

 ards the opposite corner at the other end, whereby is further 



Fig. 40. Pieces of sledge keels made of bone. Dunholm. ^/з. 



ensured that the friction under the runner of the sledge is 

 distributed evenly and in an advantageous manner; for other- 

 wise the sledge would receive an uneven side pressure at the 

 bottom of the track formed by the shoe which would tend to 

 make it run off the track. Furthermore, it is of interest to note 

 that not only the placing of the holes but also the boring of 

 them has been made on definite principles, they being bored 

 obliquely to each other (Ryder, too, has observed this)^) so 

 that the mouths of the two rows on the upper side of the shoe 

 lie a little closer to one another than on the under side^). 



M Ryder 305. 



^) I convinced myself of this by sticking two pencil handles into the holes 

 from above, their upper tips met each other at an acute angle. 



