rll.MTKi; VIII. 



kll . n,,. position i- transverse when the edge- makes an 



tfith the line of section, or the knife in that 



1 to 1 Ii * "^'Y'" or *^*X'/ when 



,. an gle with thai line. The difference 



/ O f the two positions is that the oblique 



IB-angled wedgt than the transverse 



I, the following reasons : Neglecting for the 



n{ the distinction between the cult ing-facets and the 

 x|ll the blade . which are distinct usually because they 



;n,o! to the same angle),* it is clear that the knite 

 IgO, die an-'le of which depends on the relation 

 en tin- hei'j-ht of its ba-e and the distance from the 

 the edf With the same base the angle becomes 

 in,,. (ute the greater the distance from edge to base. 

 \ . '.. Ranting the knife we can effect what is equivalent 

 .HI increase in the distance from edge to base ; for we can 

 tlni- inc: die distance between the point of the edge 



uhich lirM touches the object, and the point of the back 

 ictly, of the back edge of the under cutting-facet) which 

 it. When the- knife is set transversely,, the line 

 aloiiLT which anv point of it traverses the object is the 

 >li< possible from edge to base of the wedge, and the 



aii'j'le of \\ed-_re is the least acute obtainable with 

 dial km Km if it is set as obliquely as possible, the line 



which any point of it traverses the object traverses the 

 knife from heel to tor, that is, along the greatest possible 

 from rd'jv to base, and therefore affords jirttct i<-<i / 1 1/ 

 a much ni"iv acute-angled wedge than in the first case ; and 

 'ii, of course, for intermediate positions. (Seethe sterco- 

 'rical constructions of the-e relations bv SCHIEFFERDECKEK, 

 p. 11": and also with more instructive figures, 

 ' Ueber die lledeutmig des M e.-serhalt ers in der 

 in N//.-.//I /. med.-naturw. Sr<-fi<>/i <l. Sicbm- 



microtome knifi .Mij.osrd of I \\-o plane Mirfaces- 

 '"ttii \\lii.-li meet one another at an a>cute 



:ni-l posteriorly j..in ., n t< the uppei- and K.wci- 

 ome good agures of .lilVeivntly shai>.-.l knives 

 CHIEPPEB :EE, Das Mikroskop., p. 115, 

 quoted below). It will |,,. sen, t| l: ,t the 

 form a u,-|,i,.,l on to tli.- Made |, v the base. 



