Sur un hydrate de soufre

in Bulletin de la Classe des Sciences. Académie Royale de Belgique (1906), (7), 452-459

Spring, W. Bulletin de la Classe des Sciences, Academie Royale de Belgique (1906), 1906, 452-59; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). If ... [more ▼]

Spring, W. Bulletin de la Classe des Sciences, Academie Royale de Belgique (1906), 1906, 452-59; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). If one lets sulfurous acid in water and hydrogen sulfide work on the other, then Polythionic acid form and sulfur, what latter after DEBUS (Chem. News 57. 87) a new allotropic modification with the ability to form with water a colloidal solution is to be (sulfur δ). The alleged Pentathionic acid shows up with intensive illumination not as an homogeneous body, but as a colloidal solution, and the sulfur δ of DEBUS not a allotropic modification, but a hydrate is S8•H2O. One receives it, if one removes and up to the constant weight in the vacuum dries the acid from with above reaction the formed S by months-long dialyze with daily fresh water, as a yellowish, partially translucent mass from conchoidal break; there is 51.6% sulfur when washing with CS2. The part unsolvable in CS2 dismisses from about 80° at water, with the melting point of the S the formula S8•H2O appropriate quantity (S8 = molecular size of the firm S!). The density of hydrate pressed in cylinder form amounts to with 19°, related to water of 4°, 1.9385; meadow after 93.6/2.07 6.4/1 = 51.6; = 100/51.6 = 1.9380 on octahedral S, if were residual insoluble S not after removal water in CS2. Powdered hydrate loses 2.41% H2O, the pressed 1.33% with 7-monthly standing over H2SO4; it thus has a vapor pressure. A part of hydrate is destroyed; simultaneous increased its density. If the drained body with water remains in contact, then the density decreases again; it exists thus a condition of the S, which connects itself directly with water, and which delivers the water in the dry medium again. In the desiccator partially S give in powder form 3.1%, in the pressed condition 5.8% at CS2 in solution dehydrated. Pressure favors thus the transition of the matter to a condition of larger density. Reprinted with the permission of the American Chemical Society. Copyright © 2010. American Chemical Society (ACS). All Rights Reserved. [less ▲]

Sur un nouvel acide de l'étain

in Bulletin de la Société Chimique de Paris. 3e série (1889), I

Sur un phénomène d'optique atmosphérique

in Ciel et Terre (1972), 88

Not Available

Sur une forme monoclinique de l'ilvaite

in Annales de la Société Géologique de Belgique (1967), 91

Sur une mesure locale de l'erreur de discrétisation par éléments finis

Report (1993)

Local discretization errors are commonly done by inspecting local equilibrium errors. The difficulty lies in the fact that there is not, in general, a local convergence of equilibrium. Our point of view ... [more ▼]

Local discretization errors are commonly done by inspecting local equilibrium errors. The difficulty lies in the fact that there is not, in general, a local convergence of equilibrium. Our point of view is that desequilibrium has to be considered in its natural frame, which is the dual space. In other word, desequilibrium has to be measured by the work that it is able to produce. Such quasi-local error measures are presented. [less ▲]

Sur une modification lente de la constitution des solutions de certains sels

in Archives des Sciences Physiques et Naturelles (1910), 29

Spring, Archives des Sciences Physiques et Naturelles (1910), 29, 145-56; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). Solns. of a number of ... [more ▼]

Spring, Archives des Sciences Physiques et Naturelles (1910), 29, 145-56; SciFinder (Chemical Abstracts Service: Columbus, OH); https://scifinder.cas.org (accessed July 8, 2010). Solns. of a number of salts (KNO3, KBr, Na2SO4, K2Cr2O7, ZnSO4, CuCl2, CuSO4, MnCl2, AlCl3, etc.) prepared in 1905 and kept at ordinary temp. from the action of direct sunlight were examined at intervals during the following four years and were found to become more and more transparent. The degree of transparency was judged by the degree of luminosity in the soln. of a beam of light projected through it by an electric lantern (50 volts and 12 amp.). To ascertain if there had been any molecular change in the solns., during the four years the conductivities of the original and the four year old solns. were determined and compared. The cond. of the original solns. was determined from portions of the 4-year-old solns. which had been evaporated to dryness and redissolved to the original vol. In the majority of cases the 4-year-old solns. showed markedly smaller conds. This may be explained by a hydrolysis of the salt which occurs when the soln. is first made. The "hydrate" [hydroxide?] thus formed is in a colloidal condition and does not affect the electrical resistance; this colloidal soln. by reflection renders more luminous a beam of light passed through the soln. The free acid initially present is the cause of the high conductivity of the solution. In the old solns. the colloidal hydrate and the free acid have greatly decreased, and the conductivity is therefore smaller than before. The state of equilibrium of such a hydrolysis, when once displaced by change of temp., etc., is restored very slowly. The soln. becomes more optically transparent owing to the gradual disappearance of the colloidal hydrate. The K2Cr2O7 soln. alone was anomalous and showed a decrease in resistance of almost one-half on standing four years. This soln. had become yellow, but on evaporating the soln. and redissolving to the same vol. the color was reddish yellow as in the original soln. Reprinted with the permission of the American Chemical Society. Copyright © 2010. American Chemical Society (ACS). All Rights Reserved. [less ▲]

Sur une modification lente de la constitution des solutions de certains sels

in Bulletin de la Classe des Sciences. Académie Royale de Belgique (1910), (1), 11-22

Sur une relation entre l'élasticité optique et l'activité chimique dans un cristal de spath d'Islande

in Bulletin de l'Académie Royale des Sciences, des Lettres et des Beaux-arts de Belgique. Sciences. 3e série (1887), XIV(7), 13-14

Les surcoûts collectifs de la désurbanisation : quand la mobilité dessine la ville

in La Cemathèque (2000), (4), 8-11

Les surcoûts de l’étalement urbain

Conference given outside the academic context (2010)