On the Magnetic Disturbance on December \4>th. 1862. 471 



measured portion ; and in a third portion the barium was estimated 

 as sulphate. The results of these determinations are given below, 

 the camphoric acid being assumed as correct. They lead to the 

 conclusion that the solution contains the elements of one equivalent 

 of anhydrous camphoric acid, one of oxygen, and one of baryta. 

 Atomic weight. Calculated ratio. Found. 



C^H^Og 182 25-12 25*12 



O 16 2-20 2-07 



Ba 2 153 21-12 21-51 



the reaction being 



C 10 H u O 3 + Ba 2 O 2 =C 10 H u O s Ba 2 . 

 That the substance formed is to be regarded as the baryta salt of the 

 peroxide of camphoryle, and not as the camphorate of the peroxide of 

 barium, is proved by the reactions of the solution, which does not 

 give peroxide of hydrogen when decomposed by acids, or a precipitate 

 of the hydrated peroxide of barium when heated with a solution of 

 baryta. 



The organic peroxides constitute a new and peculiar group of 

 chemical substances characterized by reactions never hitherto found 

 in any compound of carbon, and which materially extend our views 

 of the possible properties of the so-called organic combinations, and 

 of their analogies to inorganic substances. They are the organic 

 representatives of chlorine in the same sense as the oxides of the 

 compound ammoniums are the representatives of potash, and in a 

 yet closer sense than ether and alcohol resemble the oxide and its 

 hydrate, or than ethyl e or marsh-gas are analogous to hydrogen. 

 This analogy is of a profound character, not consisting merely in 

 the analogy of symbolic form, but in the absolute identity of reactions. 

 The admitted analogies of the peroxide of chlorine have as it were 

 their maximum in the organic peroxide. Not only is chlorine re- 

 presented in the peroxide, but hydrochloric acid is represented in the 

 organic acid, and a series of parallel equations may readily be con- 

 structed, showing the identical character of the reactions of the two 

 classes of substances. Both bleach a solution of indigo, oxidize the 

 protosalts of iron and manganese, decompose water under the in- 

 fluence of sunlight, and evolve oxygen with an alkaline peroxide, 

 forming the salt of the corresponding acid. 



"On the Magnetic Disturbance which took place on the 14th of 

 December 18G2." By Balfour Stewart, M.A., F.R.S. 



On the 14th of December 1862, a magnetic disturbance occurred 

 about 6 o'clock in the afternoon, and was registered by means of the 

 Kew magnetographs. As usual it was accompanied by an auroral 

 display and by earth-currents, and the latter phenomena were ob- 

 served at Greenwich by means of a system of telegraphic wires which 

 had recently come into the possession of the Astronomer Royal. 



By the kindness of Mr. Airy, the Kew Observatory has been 

 favoured with a copy of the curves which represent the earth-cur- 

 rents collected at Greenwich during the progress of this disturbance ; 

 and a comparison of these with the Kew magnetograph curves will 

 form the subject of the following paper. It will, however, first be 



