III. Botany and Zoology. 



1. On Right-handed and Left-handed Relatiotis in Space — 

 "£'" ■■■■M-.Miiiir is extraded from J. Clerk-Max^ , ii's lYe:ui>e ,. n 

 :nd Magnetism, i, p. J.). " Tn this i reatise, the mo- 

 tlo . i|S " r ' r;i!i>l:irir»)i along any axis, and of rotation around that 

 a\i>. will in- assumed to he of'ihe same si-n, when their directions 

 correspond to those of an ordinary or right-handed screw." " The 

 muscles of the arm when we turn the upj>or 

 >ide of the right hand outward, and at the same time thru-t the 

 ''■tii'I forward, will impress the riudit nan led screw motion on the 

 memory more firmly than any verbal definition. A common cork- 

 * f ' r '--" nuiy he used as a material svmhol of the same relation." " 

 "This is the right-handed svstem whiVh is :i.l« .pti-.l in Thomson and 

 Iait's Xatwxil /'hi/,,, ,-!■•,. <_'!:!. The opposite, or left-handed 

 system, is adopted in Hamilton and Tail's Quaternions." 



It appears, therefore, that the view which •' A. Gray, Darwin, 

 :i:"l r.eiitham" are blamed for taking, is regarded as the natural 

 one by Clerk Maxwell. Thomson, ,-.. am ,,_ tl mathematicians 

 and physicists. For avoiding a.-hi-aiit v, "Prof. \V. H. Miller lias 

 *ugg< >ted t« mi that, is tin tendrils of* th< vim an riu'htd i led 

 screws, and those <>i ; ,,_. two systems of rela- 



tions in sj, ace might lie called those of the vine and hop respect- 

 !v, 'ly." Maxwell, 1. o. This botanical illustration is readily 

 ll "'lervtood, hut is not altogether a happy one. By " the vine," 

 in of tin I'niti I States, the -rape-vine (as we call it) 

 : - 

 laid hold, and then, when half the coil is in one direction the 

 other is necessarily in the reverse. And the hop has no tendrils: 

 the meaning is that its stain, in • ; ' ' to left, 



!• e., of the outside observer; while in the larger number of 

 <' :i '' -'" ■;- (01' which Hindu e, d.' i '■•>:>•, ■h-nhis. it-./ is the better 

 fcion. Hut the terms 

 " hop^ystem and viue-svstem" are obviously impracticable in de- 

 scriptive liotanv. "With the sun" and " against the sun"--the 

 terms which Da >wi . u ? made 



"sed in a different sen-e and connection, and anti-heliof ropic for 

 tee 'oimterpart is too Iom_i' :iud awkward a word. /Sntro/n'c and 

 u i<titri> t ,ir mioht ser\. the purpo^- ami it agreed upon would do 



by the position of the observer, whether within or without the 

 circle or coil. Thus, in sa vino- t hat the hop in twining ■•follows 

 the course of the sun." it' matters nor wi. ether the coil and the 

 i'1'ii it path ot tin -m b regai I d U mt - tside or from 



i tfiblioteque 



Universelle. Jan.. 1877. pp. l:b— The double turn of the helix 

 in attached tendrils excited the author's attention, but he finds, as 

 Am. Jour. Sci.-Thibd Series, Vol. XIH, No. 77.-Mat, 1877. 



