DELINEATION OF NATURE. 81 



will be considered in another part tf this work; will teach us 

 how, in the course of ages, mankind has gradually attained 

 to a partial msight into the relative dependence of phenomena. 

 My duty is to depict the results of our knowledge in all their 

 bearings with reference to the present. In all that is subject 

 to motion and change in space, the ultimate aim, the very ex- 

 pression of physical laws, depend upon mean numerical values. 

 which show us the constant amid change, and the stable amid 

 apparent fluctuations of phenomena. Thus the progress of 

 modern physical science is especially characterized by the at- 

 tainment and the rectification of the mean values of certain 

 quantities by means of the processes of weighing and meas- 

 uring ; and it may be said, that the only remaining and wide- 

 ly-diffused hieroglyphic characters still in our writing num- 

 Icrs appear to us again, as powers of the Cosmos, although 

 in a wider sense than that applied to them by the Italian 

 School. 



The earnest investigator delights in the simplicity of nu- 

 merical relations, indicating the dimensions of the celestial 

 regions, the magnitudes and periodical disturbances of the 

 heavenly bodies, the triple elements of terrestrial magnetism, 

 the mean pressure of the atmosphere, and the quantity of heat 

 which the sun imparts in each year, and in every season of the 

 year, to all points of the solid and liquid surface of our planet. 

 These sources of enjoyment do not, however, satisfy the poet 

 of Nature, or the mind of the inquiring many. To both of 

 these the present state of science appears as a blank, now that 

 she answers doubtingly, or wholly rejects as unanswerable, 

 questions to which former ages deemed they could furnish 

 satisfactory replies. In her severer aspect, and clothed with 

 less luxuriance, she shows herself deprived of that seductive 

 charm with which a dogmatizing and symbolizing physical 

 philosophy knew how to deceive the understanding and give 

 the rein to imagination. Long before the discovery of the 

 New World, it was believed that new lands in the Far West 

 might be seen from the shores of the Canaries and the Azores. 

 These illusive images were owing, not to any extraordinary 

 refraction of the rays of light, but produced by an eager long- 

 ing for the distant and the unattained. The philosophy of 

 the Greeks, the physical views of the Middle Ages, and even 

 those of a more recent period, have been eminently imbued 

 with the charm springing from similar illusive phantoms of 

 the imagination. At the limits of circumscribed knowledge, 

 as fiom some lofty island shore, the eye delights to penetrate 

 D2 



