Scientific Reviews. 265 



Silicon. We are sure our readers will feel grateful to us for the 

 information we are the happy instruments of conveying to them, 

 by quoting the following passage from page 432. 



" When describing the structure of the radiant medium, it was shewn that 

 eight atoms, circumscribing an octaedral cavity, might be regarded as its mole- 

 cule. Of all the forms of the universe, this, then, may be regarded as the most 

 extensively diffused ; and though, in the radiant medium the atoms are prevent- 

 ed from cohering, yet where atoms are sufficiently near each other, this form, 

 composed of eight atoms, with an octaedral cavity, may be constantly expected. 

 It is that which bears the most intimate relationship to the matter which occu- 

 pies the celestial spaces, and this, as well as the ease with which atoms may group 

 in this form, will induce to its evolution. It is very natural to assume that this 

 body must be silicon, which ia, of all substances in the earth, by far the most 

 universally diffused." 



We have neither time nor space to refer to all the inconclusive 

 conclusions as to forms which the book contains ; for one of the 

 very worst, we refer to Alumina, pages 448-9. The following on 

 Iron is too exquisite to be omitted. 



" It has been shewn, that a particle of alumina consists of atoms circumscrib- 

 ing a cavity, which is a hexagonal prism ; that the base of potass consists of 

 atoms circumscribing a pentagonal bipyramid ; that the base of silica consists of 

 atoms circumscribing a tetragonal bipyramid ; that the base of lime consists of 

 atoms circumscribing a triangular bipyramid. What form shall possess such 

 eminence in nature as to be composed of atoms circumscribing a tetraedal cavity, 

 which is the form of the ultimate atom itself ? This is iron, a substance so uni- 

 versally diffused in nature, that it would be difficult to find any natural body 

 whatever, in which we could positively say that there was no particle of iron in 

 it." P. 463. 



And on the distribution of iron we have the following : " Such 

 are some of the forms of combination in which iron is most fre- 

 quently found in nature and in the laboratory ; but to trace the 

 modes of its existence minutely would require volumes. It is per- 

 haps generated at the first breath of the youngest creature in the 

 world, and it is abundant in the oldest granite" ! ! ! Children 

 breathing iron ! Truly we have reached the iron age at last. And 

 yet all this is philosophy ; it forms part and parcel of the economy 

 of nature. But it is ridiculous to treat such fantasies with any 

 thing like serious attention. Lest our readers, however, should 

 think we select the weakest portions, we request as many of them 

 as can lay hands upon the book, to read the chapter upon iron, 

 which professes to be one of the greatest efforts it contains, and to 

 judge for themselves of the ease with which whole hosts of pheno- 

 mena are accounted for and explained. Mr. M'Vicar's atomic 

 forms are in truth little better than a tissue of random guesses, 

 upon which the powers of an ingenious and gifted mind have been 

 idly wasted ; for we reckon as merely accidental, or, more proper- 

 ly perhaps, natural coincidences, all the instances of agreement be- 

 tween the combinations of which his forms admit, and those ac- 

 tijally found in nature,— coincidences which would probably be 

 found by assuming any other form for the ultimate atoms, and 

 building them according to known physical laws. 



