He has, he adds, tested gold made by alchemists, and found that it will not withstand six or seven exposures to fire.
This enabled the observer to make exposures of any desired length, and, through the cumulative action of light on extremely sensitive surfaces, to obtain permanent accurate pictures of celestial objects so faint as to be completely invisible to the eye, even when aided by the most powerful telescopes.
East of the Sao Francisco it may be divided into three distinct regions: a rough limestone plateau rising gradually to the culminating ridges of the Serra da Chapada; a gneissose plateau showing extensive exposures of bare rock dipping slightly toward the coast; and a narrower plateau covered with a compact sandy soil descending to the coastal plain.
The superintendent of the Ninth Census, 1870, presented a computation 01 the effects of this causefirst, through direct losses, by wounds or disease, either in actual service of the army or navy, or in a brief term following discharge; secondly, through the retardation of the rate of increase in the colored element, due to the privations, exposures and excesses attendant upon emancipation; thirdly, through the check given to immigration by the existence of war, the fear of conscription, and the apprehension abroad of results prejudicial to the national welfare.
Abney as far as 20,000 A, but long exposures are necessary.
It is possible to learn from them more regarding the social and political condition of the period than perhaps from any other source, for they abound, not only in exposures of religious abuses, and of the prevailing corruptions of society, but in references to many varieties of social injustice and unwise customs, in racy sketches of character, and in vivid pictures of special features of the time, occasionally illustrated by interesting incidents in his own life.
Where accurate differential observations or photographs involving other than instantaneous exposures have to be made, the additional condition is required that the optical axis of the telescope shall accurately and automatically follow the object under observation in spite of the apparent diurnal motion of the heavens, or in some cases even of the apparent motion of the object relative to neighbouring fixed stars.
This is an unquestionable drawback when long exposures near the meridian are required.
Good rock exposures were found containing coal and fossils.
If three plates (or three sets of exposures on one plate) are taken at intervals of six months, when the stars in the region have their maximum parallactic displacements, the first and third plates serve to eliminate the proper motion of the star, and the detection of a parallax is easy.
On the southern exposures of the Himalaya that carry perpetual snow, along all that part of the system that lies between Sikkim and the Indus.
Some of the best-known exposures are in the ranges which rise above the western plains, such as the Rankin Range on the Darling and the Kokopara Range to the north of the Murrumbidgee.
Regarding now the outcrops of bed-rock, there are exposures of Algonkian (doubtful, and at most a mere patch on Pilot Knob), Archean, Cambrian, Ordovician, Silurian, Devonian, sub-Carboniferous and Carboniferous.
This significant but evanescent phenomenon, which represents the direct emissions of a low-lying solar envelope, was photographed by William Shackleton on the occasion of an eclipse in Novaya Zemlya on the 9th of August 1896; and it has since been abundantly registered by exposures made during the obscurations of 1898, 1900, 1901 and 1905.
Sir William Huggins repeated the experiment on Winnecke's comet in 1868, Progress only with long exposures could autographic im ?'
For it made long exposures possible; and obtained the same bands, and traced them to their babylonische Mondrechnung (1900); J.
The Slieve Bloom Mountains are thus formed of a dome of Old Red Sandstone folded on a core of unconformable Silurian strata; while in several cases the domes are worn through, leaving rings of Old Red Sandstone hills, scarping inwards towards broad exposures of Silurian shales.