384 Proceedings of the Royal Societi/, 



" To point out all the objects worthy of inquiry in chemistry, 

 would occupy the time appropriated to many sittings of the 

 Society. I cannot, however, avoid mentioning amongst import- 

 ant desiderata, the knowledge of the nature of the combinations 

 of that principle existing in fluor or Derbyshire spar, and 

 which has not yet been obtained pure ; the relations of that 

 extraordinary fact, the metallization of ammonia ; and the con- 

 nexion between mechanical and chemical phaenomena in the 

 action of voltaic electricity. I must congratulate the Society 

 on the rapid advances made in the theory of definite pro- 

 portions, since it was first advanced in a distinct form by 

 the ingenuity of Mr. Dalton. I congratulate the Society on 

 its progress, and on the promise it affords of solving the re- 

 condite changes owing to motions of the particles of matter, 

 by laws depending upon their weight, number, and figure, 

 and which will be probably found as simple in their origin, and 

 as harmonious in their relations, as those which direct the 

 motions of the heavenly bodies, and produce the beauty and 

 order of the universe. 



'* The crystallizations or regular forms of inorganic matter 

 are intimately connected with definite proportions, and depend 

 upon the motion of the combinations of the elementary par- 

 ticles : and both the laws of electrical polarity, and of the po- 

 larization of light, seem related to these phaenomena. As to 

 the origin of the primary arrangements of the crystalline 

 matter of the globe, various hypotheses have been applied, 

 and the question is still agitated, and is perhaps above the 

 present state of our knowledge ; but there are two principal 

 facts which present analogies on the subject : One, that the 

 form of the earth is that which would result, supposing it to 

 have been originally fluid ; and the other, that in lavas, masses 

 decidedly of igneous origin, crystalline substances similar to 

 those belonging to the primary rocks, are found in abundance. 



" In following the sensible phaenomena of nature from the 

 motions of the great masses of the heavenly bodies, which 

 first impress the senses and affect the imagination, to the 

 changes individually imperceptible, which produce the phseno- 



