...How to retrace their steps was now the problem, apparently insoluble... 
George Grote 「The Two Great Retreats of History」
...“I am glad to be able to resolve a difficulty that at one moment seemed insoluble...
Rafael Sabatini 「Captain Blood」
...An inspection under the microscope tells us that the contents of thewhite cells are composed of very fine, opaque grains, insoluble inwater and of greater density...
Jean Henri Fabre Alexander Teixeira de Mattos 「The Glow-Worm and Other Beetles」
...On all sides it was regarded as an insoluble enigma...
Ernst Haeckel 「The Evolution of Man」
...The problem is probably insoluble...
Northcote W. Thomas 「Kinship Organisations and Group Marriage in Australia」
...The problems raised by the phratriac nomenclature are complex andprobably insoluble...
Northcote W. Thomas 「Kinship Organisations and Group Marriage in Australia」
...These accidental or intentionalimpurities may mostly be detected by heating the carmine with liquidammonia, which entirely dissolves the colouring matter and leaves theimpurities in an insoluble state...
George Field 「Field's Chromatography」
...The metallic compounds formed by the combination of persulphomolybdicacid with a base are pulverulent, in many cases of a red colour, and forthe most part insoluble in water...
George Field 「Field's Chromatography」
...The red being insoluble therein isprecipitated, while the acetate of lead remains dissolved...
George Field 「Field's Chromatography」
...It may, indeed, be renderedcomparatively insoluble in water by ignition; but the anhydrous oxide soobtained is nearly black, and as a colour worthless...
George Field 「Field's Chromatography」
...Indeed, I haveheard it admitted by men of high intellectual attainments that thequestion was insoluble...
Simon Newcomb 「Side-lights on Astronomy and Kindred Fields of Popular Science」
...Closely connected with the problem of the extent of the universe isanother which appears, for us, to be insoluble because it brings usface to face with infinity itself...
Simon Newcomb 「Side-lights on Astronomy and Kindred Fields of Popular Science」
便利！手書き漢字入力検索
この漢字は何でしょう？？