166 NOVUM ORGANUM 



call twilight instances; they are as it were opposed to the 

 conspicuous instances, for they show the required nature in 

 its lowest state of efficacy, and as it were its cradle and first 

 rudiments, making an effort and a sort of first attempt, but 

 concealed and subdued by a contrary nature. Such in 

 stances are, however, of great importance in discovering 

 forms, for as the conspicuous tend easily to differences, so 

 do the clandestine best lead to genera, that is, to those com 

 mon natures of which the required natures are only the 

 limits. 



As an example, let consistency, or that which confines 

 itself, be the required nature, the opposite of which is a 

 liquid or flowing state. The clandestine instances are such 

 as exhibit some weak and low degree of consistency in 

 fluids, as a water bubble, which is a sort of consistent and 

 bounded pellicle formed out of the substance of the water. 

 So eaves droppings, if there be enough water to follow 

 them, draw themselves out into a thin thread, not to break 

 the continuity of the water, but if there be not enough to 

 follow, the water forms itself into a round drop, which is the 

 best form to prevent a breach of continuity; and at the mo 

 ment the thread ceases, and the water begins to fall in drops, 

 the thread of water recoils upward to avoid such a breach. 

 Nay, in metals, which when melted are liquid but more 

 tenacious, the melted drops often recoil and are suspended. 

 There is something similar in the instance of the child s look 

 ing-glass, which little boys will sometimes form of spittle 

 between rushes, and where the same pellicle of water is ob 

 servable; and still more in that other amusement of children, 

 when they take some water rendered a little more tenacious 

 by soap, and inflate it with a pipe, forming the water into a 

 sort of castle of bubbles, which assumes such consistency, 



