CORRIGEXDA. 



Page 2G1, at end, add lo. — Quaternions as a Practical Instnnnent of 

 Physical Research. By A. M'Aulay, M.A. 



Page 298, line 4 from top, ./b/- iron from Vesuvius, read iron ore from 

 Vesuvius. 



Page 298, line 10 from top, for magnetic particles 'OG, read magnetic 

 particles 'G. 



Page 298, line 30 from top,./o/- Wallerawang, like the preceding, also, 

 from irregular deposits, read Wallerawang, from irregular deposits. 



Page 298, line 36 from top,, /or about quarter across, read about quarter 

 inch across. 



Page 300, line 2G from top,, /or or •14 per cent., read or '09 per cent. 



Page 303, line 18 from top,,/w/- statements which are of so man,v years 

 standing, read (statements which are of many years standing). 



Page 305, line 7 from top, for (by the bichromate volumetive process, 

 read (by the bichromate volumetric process). 



Page 311, line 41 from top,,/(jr added to thin solution, kc, read added 

 to their solutions, &c. 



Page 316, line 3 from top,,/br by the oxidation of silicate, read by the 

 oxidation of silicide. 



Page 316, line 24 from top, for ^thiops (Martialis Lemeryi), read 

 jEthiops Martialis Lemeryi. 



Page 319, line 13 from top, for It had the following, read it had the 

 following. 



