LecounVs Magnetic Properties of Iron Bodies. Gl 



of the strongest oil of vitriol yield, by slow distillation from a 

 glass retort into a refrigerated receiver, concentrated acetic acid. 

 A small portion of sulphurous acid, which contaminates it, may 

 be removed by redistillation, from a little acetate of lead. 2d, 

 Or 4 parts of good sugar of lead, with 1 part of sulphuric acid 

 treated in the same way, afford a slightly weaker acetic acid. 3d, 

 Gently calcined sulphate of iron, or green vitriol, mixed with 

 sugar of lead in the proportion of I of the former to 2| of the 

 latter, and carefully distilled from a porcelain retort into a cooled 

 receiver, may be also considered a good economical process. Or 

 without distillation, if 100 parts of well dried acetate of lime be 

 cautiously added to 60 parts of strong sulphuric acid, diluted 

 with 5 parts of water, and digested for 24 hours, and strained, a 

 good acetic acid, sufficiently strong for every ordinary purpose, 

 will be obtained. 



•' The distillation of acetate of copper or of lead per 5e, has also 

 been employed for obtaining strong acid. Here, however, the 

 product is mixed with a portion of the fragrant pyro-acetic spirit, 

 which it is troublesome to get rid of. Undoubtedly the best pro- 

 cess for the strong acid is that first described, and the cheapest 

 the second or third. When of the utmost possible strength its 

 sp. gravity is 1.062. At the temperature o: 50^ F. it assumes 

 the solid form, crystallizing in oblong rhomboidal plates. It has 

 an extremely pungent odour, affecting the nostrils and eyes even 

 painfully, when its vapour is incautiously snuffed up. Its taste is 

 eminently acid and acrid. It excoriates and inflames the skin." 



" EtiUiVALKNTs Chkmical." Under this head Dr. Ure has 

 given a Dissertation on the Atomic Theory, which to us seems 

 to be the best that has yet appeared on this interesting and funda- 

 mental doctrine. Had our present limits permitted us, we should 

 have laid it entire before our readers. It shall, if possible, appear 

 in our next. We mean also, as soon as opportunity will permit, 

 to advert to other new views of practical cliemistrv, opened up 

 by Dr. Ure, and which we consider highlv valuable. 



The facility of reference would have been iniproved hod the 

 author, where any article occupies a large space, put its whole 

 title at the top of the pages coiit;iining it, instead of only the 

 three initial letters. 



A Description of l/ie changeable Magnetic Properties possessed 

 h}l all Iron Bodies, and lite different i]{fects produced I'l/ the 

 same 071 Ships' Compasses. By P. L>xouni', iMidsliipuum in 

 the Royal Navy. Svo, pp. 56. 



This appears to be a most useful practical little work. The 

 author corrects several erroneous opinions that have been enter- 

 tained, and points out a variety of facts which have not before 



been 



