CHAP. XIV.] SCIENCE AND FREE WILL. 443 



possible directions of lines in the crystal ; but it is to be ex- 

 pected that in phenomena of higher complexity there will be 

 a far greater number of singularities, near which the axiom 

 about like causes producing like effects ceases to be true. 

 Thus the conditions under which gun-cotton explodes are 

 far from being well known ; but the aim of chemists is not 

 so much to predict the time at which gun-cotton will go off 

 of itself, as to find a kind of gun-cotton which, when placed 

 in certain circumstances, has never yet exploded, and this 

 even when slight irregularities both in the manufacture and 

 in the storage are taken account of by trying numerous and 

 long continued experiments. 



In all such cases there is one common circumstance, the 

 system has a quantity of potential energy, which is capable of 

 being transformed into motion, but which cannot begin to be 

 so transformed till the system has reached a certain configura- 

 tion, to attain which requires an expenditure of work, which 

 in certain cases may be infinitesimally small, and in general 

 bears no definite proportion to the energy developed in con- 

 sequence thereof. For example, the rock loosed by frost and 

 balanced on a singular point of the mountain-side, the little 

 spark which kindles the great forest, the little word which 

 sets the world a fighting, the little scruple which prevents 

 a man from doing his will, the little spore which blights all 

 the potatoes, the little gemmule which makes us philosophers 

 or idiots. Every existence above a certain rank has its 

 singular points : the higher the rank, the more of them. At 

 these points, influences whose physical magnitude is too 

 small to be taken account of by a finite being, may produce 

 results of the greatest importance. All great results pro- 

 duced by human endeavour depend on taking advantage of 

 these singular states when they occur. 



There is a tide in the affairs of men 



Which, taken at the flood, leads on to fortune. 



The man of tact says "the right word at the right 

 time," and, " a word spoken in due season how good is it ! " 

 The man of no tact is like vinegar upon nitre when 



