Report of the Annual MeetingJ. Murray., 1919 |
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acid action adsorbed adsorption alkali amount anion annually anode Brit British calcium carbon casein cataphoresis cathode cations cell cellulose cent Chem chemical chloride chromic oxide clay coagulation colloid chemistry colloidal silver colloidal solution Committee compounds concentration diaphragm disperse effect electrical endosmose electrolytes Elektro-osmose emulsifying emulsions Energy of rupture enzyme fibres filter forestry free places free-place Freundlich gelatin hæmoglobin hydrogen ibid Inst investigation ions Irish Naturalist Jour Journ Koll liquid membrane method milk Museum N. H. Soc nitrate notch observed obtained osmotic pressure oxide oxygen particles peat peptised permeability phase phenomena Phys plant precipitation present Proc produced Professor purification reaction rennet Report Royal Astr salts Schwerin sewage silver silver chromate Society sodium sodium chloride soil solid sols soluble Steel substances surface surface tension suspension Table temperature tension test-piece tests theory timber tion Trans viscosity Zeit
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Page 2 - ... removes the rouge or the carbon black from the paper because it adsorbs these substances more strongly, and everything, therefore, goes through the paper. That this is the true explanation can be shown in two ways. In the first place, the experiment does not succeed if the rouge or the carbon is too coarse. In the second place, Spring showed that" we are dealing with an adsorption of carbon black by filter-paper.
Page xviii - To summon meetings in London or elsewhere for the consideration of matters affecting the Interests of Zoology or Zoologists, and to obtain by correspondence the opinion of Zoologists on matters of a similar kind, with power to raise by subscription from each Zoologist a sum of money for defraying current expenses of the Organisation. Sec.- — Prof.
Page 140 - ... 631. The dissipation of the vapour produced at the surface of the platina, and the contact of fresh oxygen and hydrogen with the metal, form no difficulty in this explication. The platina is not considered as causing the combination of any particles with itself, but only associating them closely around it ; and the compressed particles are as free to move from the platina, being replaced by other particles, as a portion of dense air upon the surface of the globe, or at the bottom of a deep mine,...
Page 140 - He observed the retardation of action caused by admixture of foreign gases, and he rightly and acutely concluded that all these effects of reaction and retardation depend upon the exertion of that attractive force possessed by many bodies, especially those which are solid, in an eminent degree, and probably belonging to all; by which they are drawn into association more or less close, without at the same time undergoing chemical combination though often assuming the condition of...
Page 5 - The univalent caesium ion has a greater precipitating power than the bivalent zinc, cadmium, nickel, and uranyl ions ; and about the same precipitating power as the bivalent copper, manganese, and magnesium ions. The trivalent aluminum ion has about the same precipitating power as the bivalent calcium ion, and distinctly less precipitating power than bivalent strontium and barium ions. The specific nature of the adsorption comes out extraordinarily clearly with sulphur, about the only orthodox thing...
Page 2 - ... black filtrate is obtained and the filter-paper is no longer black. All the carbon black has passed through the filter-paper. The same thing can be done with rouge, except that a red filtrate is obtained instead of a black one. At first sight it seems as though the soap must have broken up the carbon or the rouge into finer particles, which then passed through the filter, but this is probably not so.
Page 5 - Ag > K, Na. Bivalent lead has practically the same precipitating power as trivalent aluminum. Univalent silver is nearer to bivalent uranyl and barium than to univalent potassium and sodium. If more cations had been studied we should very likely have got more distinct evidence of specific action. As it is, it takes 130 millimols NaOH per liter to coagulate the platinum and only 2.5 millimols NaCl. The change from chloride to hydroxide has a more marked effect than the change from sodium to barium....
Page 103 - Hydrous chromic oxide gives an apparently clear green solution when treated with an excess of caustic potash ; but the green oxide can be filtered out completely by means of a collodion filter, a colourless solution passing...
Page 5 - Under the conditions of Ode'n's experiments, sulphur is a negative colloid and the precipitation is therefore due to an adsorption of cations. The first thing to be noticed is that hydrogen ion is not adsorbed strongly by sulphur, the precipitating power of hydrochloric acid being much less than that of lithium, ammonium, sodium, potassium, rubidium, or caesium chloride. Instead of these univalent cations precipitating at the same concentration, the required concentration of lithium chloride is,...
Page 103 - Grimaux19 showed that glycerine prevents the precipitation of hydrous ferric oxide by caustic potash. If one ion of an electrolyte is adsorbed more than the other ion, it will tend to peptise the adsorbing material and to give rise to a colloidal solution containing positively or negatively charged particles according to the nature of the adsorbed ion. Univalent ions are not all adsorbed alike ; nor are bivalent or trivalent ions. The order of adsorption is specific with each substance. Certain univalent...