14 CLASSICS OF MODERN SCIENCE 

 admitting the air, for putrefaction. But instances of the operation 

 and effect of continuance must be collected diligently from every 

 quarter. 



V. The direction of motion (which is the fifth method of action) 

 is of no small use. We adopt this term, when speaking of a body 

 which, meeting with another, either arrests, repels, allows, or directs 

 its original motion. This is the case principally in the figure and 

 position of vessels. An upright cone, for instance, promotes the 

 condensation of vapor in alembics, but when reversed, as in inverted 

 vessels, it assists the refining of sugar. Sometimes a curved form, 

 or one alternately contracted and dilated, is required. Strainers 

 may be ranged under this head, where the opposed body opens a 

 way for one portion of another substance and impedes the rest. Nor 

 is this process or any other direction of motion carried on externally 

 only, but sometimes by one body within another. Thus, pebbles are 

 thrown into water to collect the muddy particles, and syrups are re- 

 fined by the white of an egg, which glues the grosser particles to- 

 gether so as to facilitate their removal. Telesius, indeed, rashly and 

 ignorantly enough attributes the formation of animals to this cause, 

 by means of the channels and folds of the womb. He ought to have 

 observed a similar formation of the young in eggs which have no 

 wrinkles or inequalities. One may observe a real result of this 

 direction of motion in casting and modelling. 



VI. The effects produced by harmony and aversion (which is the 

 sixth method) are frequently buried in obscurity; for these occult 

 and specific properties (as they are termed), the sympathies and 

 antipathies, are for the most part but a corruption of philosophy. 

 Nor can we form any great expectation of the discovery of the 

 harmony which exists between natural objects, before that of their 

 forms and simple conformations, for it is nothing more than the 

 symmetry between these forms and conformations. 



The greater and more universal species of harmony are not, how- 

 ever, so wholly obscure, and with them, therefore, we must commence. 

 The first and principal distinction between them is this; that some 

 bodies differ considerably in the abundance and rarity of their sub- 

 stance, but correspond in their conformation ; others, on the contrary, 

 correspond in the former and differ in the latter. Thus the chemists 

 have well observed, that in their trial of first principles sulphur and 



