Geology and Natural History. 249 
sion ~winen which we are endeavoring to escape would have been 
avoi 
In edsp ting the external point of view—now fortified by 
original authority—it is well to note that we shall be in accord 
with the modern physicists and mathematicians, and also with 
common people. ‘The ordinary screw, on which the thread ore 
left to right, is everywhere known as the right-handed screw; 
and this, with the corkscrew, is taken as the norm and ex “ponent 
of right-handed rotation a Clerk- Maxwell (Treatise on Electricity 
and ee i, 23), and ir Wm. Thomson 
nalogies which have been adduced in favor of the inside 
sioulticles are “mostly drawn from objects which have a right and 
left of their own; a building, ss — has a — and left side 
or wing beca t has a front a rear. e right t side of an 
assembly sce a over by an ard who faces the members is 
quite arbitrarily, but naturally, taken to be that on the right of 
the chairman. But the right hand figures on a drawing or 
engraved plate are taken to be those on the right hand of the 
observer, erate that the plate,*having face and back, has 
a right and left of its 
Chapter XV refers ne certain difficulties which grow out of am- 
biguous terms of ordinary language; for example, the various 
meanings of the word (jin) end or purpose, and the aertsk ds in 
the use of the terms Vature, natural, supernatural (which lead off 
into philosophy, but are here treated rather in reference to s style 
of exposition) ; also the. change which has occurred in the scope 
of the word history in natural science. 
Chapter XVI is an interesting and pertinent one, upon the man- 
ner in which facts observed under the microsco ope are describe 
Extracts from the German of Schacht, the Tanck of Payer, and 
the Italian of Gasparrini are given, an nd by their side a rendering 
in ais i Latin; and the words and letters are counted. The 
specimen so treated is diminished to considerably less 
than half the number of words and a little less than half the num- 
ber of letters. The French simmers down to one-third the number 
ess th 
Italian extract of 51 words and 256 letters is expressed in Latin of 
nean form by 21 words and 127 letters. 
Style in botanical works is discussed in Chapter XVIII, which 
all hee botanists rca ma —— age the portion which 
bo 
