Sunday is kept holiday.' But our German friends emancipated themselves even from these relics of an ancient superstition, and declared that the first day of the week should be the hardest day of all; when the whole energies, physical and intellectual, should be concentrated from minute to minute and from hour to hour (so long as the wants of nature could be postponed), on the incessant watching of three vibrating bars. To those who understand what such tasks imply, we need say nothing of this becoming Sunday's employment; but we may mention, for the information of others, that one of Gauss's most zealous pupils had almost sacrificed his life, through the consequences of a brain fever caught under the burning climate of Sicily, solely from pursuing the Sunday's relaxations of Göttingen. We repeat, that such a positive institution of Sunday term-days was disgraceful to Christendom, and it was so felt by the English philosophers, who refused to join the German confederation of magnetists in carrying out their system of observation. The confederation were therefore fain to indulge the English scrupulosity, and hence no doubt the sally in the Kosmos. When Mr. Airy (our excellent Astronomer Royal) mentioned these circumstances at the most crowded meeting which took place in the Senate-house at Cambridge, during the late visit of the British Association, the unanimous opinion of the assembly was sufficiently marked. But if Baron Humboldt had lived longer in England, or had even questioned any one competent English authority, he would have known that it would not be considered as 'sinful' by, we suppose, any scientific man in this island to read off a scale after the clock had struck twelve on Saturday night, in order to observe an extraordinary natural phenomenon. Here is an example in point. In 1836 an annular eclipse of the sun was visible in the northern part of this kingdom (where the observance of Sunday is supposed to be more strict than elsewhere) during church-time on Sunday, the 15th of May. What was the consequence? The service was postponed, and the whole population saw the phenomenon, astronomers inclusive. The usage at Greenwich Observatory we believe to be this: the whole staff are at liberty on Sunday, except when an observation is to be made of no great continuance, and which is likely to be of value to the interests of astronomy, or for the special improvement of the lunar tables;—any extraordinary or unique phenomenon would be observed as a matter of course-but computations and all other work which can be done during the rest of the week are entirely suspended. Being ourselves fully inclined to regard the usages of different countries and sects with charity, and, indeed, to admit that no absolute standard of con duct duct can be named on this subject suitable to all nations and all times, we are surprised that a cosmopolite traveller and grave sage should have on this occasion permitted himself the double indulgence of a blunder and a sneer. There is that, however, in the case before us which requires it to be judged by a more specific rule than that of national morality or individual opinion. The system of magnetic observatories in the colonies is a military one, conducted solely by military men, officers and non-commissioned officers of the Royal Artillery.* In every department of the public service complicated systems of duty must be conducted on fixed and precise rules. As artillerymen, they were engaged to work six days in the week, not seven. No option could be left to them to observe on Sundays or not, as they pleased; it would have been an unfair imputation of want of zeal upon any whose conscientious scruples or the limit of physical strength did not admit of their complying. And the importance of this rule of no work on Sundays is so great, that not to have adhered to it must have changed the whole system of observation. For the personal strength of the observatories must have received a large accession in order to overtake the exhausting labour of perpetually observing and computing. To do a sixth part more work would have required, we are certain, a far more than proportional increase of the staff, and besides must sooner or later bring upon the most zealous a sense of unremitting drudgery. A periodical absolute cessation of a kind of work in its nature calculated to produce speedy satiety, is undoubtedly on mere human principles a most wise legislative and economical provision. We reply, then, to those who wish the colonial observatories to be worked seven days a-week, in the characteristic language of the French functionary, 'It would be worse than a crime--it would be a blunder.' And where, after all, is the loss? Perhaps during the whole five years that the observations were intended to continue, a second great disturbance might not occur on Sunday, and in any period of observation six such will be observed for one that is missed. As to mean results, the omission of the seventh day is inappreciable; and if it be said that magnetic disturbances come under the class of extraordinary and unique phenomena, before which the repose of Sunday gives way as matter of common sense, we must observe that these disturbances can only be seen by watching for them; they do not yet (whatever art may one day achieve) announce themselves. To note disturbances at all on Sundays requires the usual observations to be * Colonel Sabine's Introduction to Observations at Toronto, 4to. 1845, p. 13. made made as a matter of course; and where the system of observation extends round the globe, to have universally simultaneous comparisons could not be effected otherwise. After all, we do not suppose that if the officer in command at Van Diemen's Land had been aware of the peculiar interest of the phenomenon, of which the observation was commenced on Saturday, he would have been deterred, either by conscientious scruples or by the fear of disobeying orders, from pursuing his inspection of the magnets after the clock struck twelve. But we see one circumstance in the detail of the observation as published by the Board of Ordnance,* which leads to a different conjecture; the observation at midnight was missed;' the last recorded was 11h. 45m. (local time). The facts seem to speak for themselves; no doubt our non-commissioned officer, worn out by many hours' watching, fell asleep, and perhaps was awakened to a sense of his position by the bright sun of a Sunday morning, pleasant to him. as a day civilly, at least, if not magnetically, free from perturbations. To conclude-we have carefully examined Sir James Ross's observations made at sea in the late Antarctic expedition (Phil. Trans. 1843, 1844) with a view to this question. The result is such as we should have anticipated. Sir James's short stay in the perilous seas of these high latitudes, whither he was sent expressly for the accumulation of magnetical observations, impelled him to use every favourable opportunity, whether on Sunday or not, for making such observations as, requiring but a short time, if postponed, must have been inevitably lost. From Magnetism the Baron proceeds to the consideration of the Polar lights, which are so evidently connected with it. We wish we could afford space to transcribe his excellent picture of auroral phenomena (p. 199), and his judicious remarks on their connection with circumstances purely atmospheric; we should have demurred, however, to his comparison between our Polar lights and the feeble phosphorescence (as it has been called) of the unilluminated parts of the moon and Venus; and we should also have questioned whether science is advanced by classifying under the common head of earthlight' such diverse facts as the aurora, the supposed luminosity of certain fogs, the animal light of the ocean, and the dark light' of Moser's pictures (Kosmos, p. 206, &c.); but our diminishing space warns us to be brief, and we pass on to the important class of facts more immediately connected with geology. The doctrine of the heat of the earth led us in one direction * Sabine on Observations of unusual Magnetic Disturbance, 4to. 1843, p. 87, col. 1. to to the magnetic and electric phenomena which appear to be intimately connected with it (as exemplified by the similarity of the isothermal and magnetic curves first noticed by Sir D. Brewster, and by the fact of diurnal and annual magnetic periods); but there is a very different class of effects probably also due to it-the production, namely, of hot-springs, earthquakes, and volcanoes, the elevation of continents, the rupture of strata, and the metamorphosis of rocks. This mode of presenting the connected sciences is not less elegant than just. The range of phenomena connected with volcanoes (which form as it were their middle term and most characteristic type) is startling, but cannot be denied to be ingenious. It commences with earthquakes (p. 210), emissions of gas, of water, i.e. cold and hot springs, pure or mineral; next, mud volcanoes, lavic volcanoes possessing craters, dome-shaped trachytic mountains, whose matter has been ejected, but not burst open into the crater form: lastly, elevation craters, or mountains elevated and opened at top, but without emission of lavas. Of all this we should like to have given some account, but the reader of Humboldt's writings cannot expect much new on the subject of volcanoes. Teneriffe and Pichincha are already old friends; and for European volcanoes, and, we may add, for the whole theory, our author simply reproduces the well-known views of Von Buch. In treating of geological formations the Baron describes rocks as distinguished by their origin into two divisions, which he somewhat quaintly calls endogenous and exogenous, from the alleged fact in botany that some plants increase from the exterior or by superposition of coats, whilst others are constantly pushing their fresh supplies of material from within outwards. The analogy (even supposing the botanical fact admitted, which is not the case) is undoubtedly more apparent than real, and expresses no more than the division of igneous and sedimentary rocks, with which geologists have long been familiar. Without quarrelling with names, however, we find formations divided according to their origin into four classes (p. 258). The first is the endogenous, or, as it has been better termed by some English geologists, hypogene class. It includes, according to Humboldt-1, granite and syenite, on which formations he gives some curious details, especially as to the extensive superposition of granite upon slates in the valley of the Irtysch in Siberia (p. 262); 2, quartz porphyry; 3, greenstone: 4, hypersthene; 5, euphotide and serpentine; 6, augitic rocks; 7, basalt and trachyte. The second class of rocks, which are, according to the author's view, exogenous, include sedimentary deposits of matter either dissolved or suspended in a fluid; such are-1, slates, up to the Devonian series; 2, coalformation deposits; 3, the whole series of limestones-except 4, travertine or modern fresh-water deposits; 5, deposits formed of infusoria. The third class is composed of rocks, also sedimentary, but transformed in their physical and chemical characters by the superinduced action of the endogenous rocks of the first class. This introduces us to the wide and curious field of metamorphism, which the author illustrates by an interesting collection of examples and special cases, commencing with the effects of heat upon crystals and simple substances observed in the laboratory by Rose and Mitscherlich, and on natural and artificial compounds variously cooled, by Sir James Hall and Gregory Watt (p. 271, 274, 457). Cases occurring in nature are next considered, such as the crystallization and formation of new cleavages in slates near their junction with igneous rocks, and the tendency to the development of segregated quartz in those formations (p. 272); the conversion of chalk and oolite into statuary marble, and of limestone into dolomite or into gypsum by the presence of certain intrusive rocks (pp. 272, 274, 278). The formation of quartz rock, and those in which garnet enters abundantly, is also considered as a metamorphic action. The doctrine of metamorphism has received no stronger confirmation than from the artificial production of simple minerals by processes of long-continued heat. Humboldt distinguishes those found accidentally in the slaggy produce of furnaces and those which have been directly prepared by art from the known ingredients. The following enumeration contains crystallized products:-of the first class or accidental-felspar, mica, augite, olivine, blende, specular iron-ore, magnetic iron-ore, and metallic titanium; of the second, or synthetically formed,-garnet, idocrase, ruby (as hard as Oriental), olivine, and augite. To the latter class we might add the very remarkable case of lapis lazuli, which is a volcanic (or at least metamorphic) product, and which has lately been produced from its elements by heat in the synthetic way; but not, we believe, crystallized. The fourth class of rocks is the conglomerate, including those sandstones which contain the débris of old formations and the 'Reibung's Conglomerate' of Von Buch, which are igneous rocks, including pebbles of the same nature with the basis (p. 282). The consideration of the arrangement of the kinds of formations now described, leads to the notice of Fossils as distinguishing types of geological equivalents, as the chronometrical indices of the age of strata-a discovery commonly thought to be modern, but which our author unequivocally attributes to Robert Hooke in 1688 (Kosmos, p. 284 and 466). Of the exquisite preserva |