THE EARTH. 



261 



preceding. " At day break," says lie, " the whole mountain of 

 Pambamarca, where we then resided, was encompassed N\-itb 

 very thick clouds ; which the rising of the sun dispersed so far, 

 as to leave only some vapours, too fine to be seen. On the side 

 opposite to the rising sun, and about ten fathoms distant from 

 the place where we were standing, we saw, as in a looking-glass, 

 each his own image ; the head being, as it were, the centre of 

 three circular rainbows, one without the other, and just near 

 enough to each other as that the colours of the internal verged 

 upon those more, external ; while round all was a circle of white, 

 but with a greater space between. In this manner these circles 

 were erected, like a miiTor, before us ; and as we moved, they 

 moveJ, in disposition and order. But, what is most remarkable, 

 though we were six in number, every one saw the phenomenon 

 with regard to himself, and not that relating to others. The 

 diameter of the arches gradually altered, as the sun rose above 

 the horizon ; and the whole, after continuing a long time, insen- 

 sibly faded away. In the beginning, the diameter of the inward 

 iris, taken from its last colour, was about five degrees and a half; 

 and that of the white arch, which surrounded the rest, was not 

 less than sixty-seven degrees. At the beginning of the pheno- 

 menon, the arches seemed of an oval or elliptical figure, like the 

 disc of the sun ; and after^vards became perfectly circular. Each 

 of these was of a red colour, bordered with an orange ; and the 



even by Dr Chladni himself. Laplace suggests the probability of their having 

 been thrown oif by the volcanoes of the moon : but the meteors which almost 

 alwaysaccomfjiy them, and theswiftnesa of their horizontal motion, militate 

 too strongly against this opinion. The greater number of philosophers con- 

 sider them, with Mr King and Sir William Hamilton, as concretions actually 

 formed in the atmosphere. This opinion is undoubtedly the most probable of 

 all ; bat in the present state of our knowledge, it would be absurd to attempt 

 any explanation of the manner in which they are formed. The masses of 

 native iron found in South America, in Siberia, and near Agnam, contain 

 nickel, as has been ascertained by Proust, Howard, and Klaproth, and re. 

 semble exactly the iron found in the stones fallen from the atmosphere. We 

 have every reason therefore to ascribe to them the same original : and this 

 accordingly is almost the uniform opinion of philosophers. Klaproth has 

 shown that real native iron is distinguished from meteoric iron by the ab. 

 sence of nickel. Upon the whole, we may consider these stony and metallic 

 masses as fragments of fire-balls which have burst in the atmosphere ; but 

 the origin and cause of these tire-balls will perhaps for ages baffle all the at- 

 tempts of philosophers to explain them. — See Thomson's St/stem of Chemistry. 



