1884.] Wickerwork, and their Degrees of Internal Freedom. 167 



equal and similar binary systems (forming paraboloids or hyper- 

 boloids) placed one over the other with corresponding joints con- 

 nected by a third system of parallel rods, whose segments between 

 two of the binary systems are therefore all equal: here the parallel 

 rods have two degrees of freedom, and the binary systems have 

 the third. 



The fact that in a binary system 4 segments are determi- 

 nable in terms of the others shows that such a system is itself 

 determined by two rods crossing three others and jointed to 

 them : — in other words, that a system of confocal hyperboloids is so 

 determined. So also a ternary system is determined by four rods 

 jointed together at different parts of their lengths by three sets of 

 four rods each. 



(3) On some Physiological Experiments. By W. H. Gaskell, 

 M.D., F.R.S. 



(4) On a method of comparing the concentrations of two 

 solutions of the same substance, but of different strengths. By 

 A. S. Lea, M.A. 



(5) On the many layered Epidermis of Clivia Nobilis. By 

 Walter Gardiner, B.A. 



