Intelligence and Miscellaneous Articles* 233 



BORURET OF IRON. 



M. Lassaigne gives the following directions for preparing this com- 

 pound : — Prepare a sub-borate of iron by precipitating persulphate 

 of iron by borax j wash and dry the precipitate, form it into a paste 

 with water, and mould it into a small cylinder - } when dry, place this 

 cylinder within a porcelain-tube, heat it red-hot, and pass pure dry 

 hydrogen over it. Boruret of iron is formed ; it acts slightly upon 

 the magnetic needle, and consists of 77*43 of iron, and 22 57 of 

 boron, or of one atom of each nearly. — Institution Journal, July 1828. 



VARIETIES OF BORAX. 



M. Payen gives the following as the results of his analysis of cry- 

 stallized boracic acid, anhydrous, prismatic, and octohedral borax,— 

 oxygen being 10. 



Crystallized Boracic Acid. 



One atom acid 44 



Three atoms water . . . 3373 



7773 



Anhydrous Borax. Prismatic Borax. Octohedral Borax. 

 Boracic acid 2 atoms . . 88 2 atoms . . 88 2 atoms . . 88 



Soda 1 atom . . 3909 1 atom . . 39*09 1 atom . . 39*09 



Water 10 atoms . 11243 5 atoms . . 56-217 



127*09 239*52 183*307 

 Ibid. 



FIGURE OF THE CELLS OF THE HONEYCOMB. 



We are indebted to our correspondent M. Fayolle, for directing 

 our attention to a paper on this subject by the celebrated Maclaurin, 

 in the Philosophical Transactions for 1 743. It appears from the no- 

 tice which M. Fayolle has communicated to us, that Fontanelle, the 

 Secretary of the Academie des Sciences, in concluding the account of 

 Kcenig's paper read before that learned body in 1739, as mentioned 

 by Mr. Sharpe in his paper on the subject, at p. 20 of our present vo- 

 lume, makes the following remark : — " La grande merveille est que 

 la determination de ces angles passe de beaucoup les forces de la ge6- 

 m£trie commune, et n'appartient qu'aux nouvelles methodes fondees 

 sur la theorie de l'infini." 



Maclaurin observes in the memoir in question, " Mr. de Reaumur 

 has informed us (Mem. sur les Insectes, torn, v.), that Mr. Koenig 

 having, at his desire, sought what should be the quantity to be given 

 to this angle, in order to employ the least wax possible in a cell of 

 the same capacity ; that gentleman had found, by a higher geometry 

 than was known to the ancients, by the method of inftnitesmals, that 

 the angle in question ought in this case to be of 109° 26'. And we 

 shall now make it appear, from the principles of common geometry, 

 that the most advantageous angle for these rhombuses is indeed, on 

 that account also, the same which results from the supposed equality 

 of the three plane angles that form the above-mentioned solid ones." 

 He then proceeds to demonstrate, by a method purely geometrical. 



New Series. Vol. 4. No 21. Sept. 1828. 2 H that 



