352 Scientific Intelligence. 



of oxygen gas, in a jar over a mercurial trough, and fused chloride of lim»» 

 introduced, for the purpose of removing hygrometric water. Three glass 

 bottles, of about three ounces capacity each, were selected for the accuracy 

 with which their glass-stoppers had been ground into them. They were 

 well cleaned and dried, no grease being allowed upon the stopper. The 

 mixture of gases was transferred into these bottles over the mercurial 

 trough, until they were about four-fifths full, the rest of the space being 

 occupied by the mercury. . The stoppers were then replaosed as tightly as 

 could be, the bottles put into glasses in an inverted position, and mercury 

 poured round the stoppers and necks, until it rose considerably above them, 

 though not quite so high as the level of the mercury within. Thus ar- 

 ranged, they were put into a cupboard, which happened to be dark, and 

 were sealed up. This was done on June 28, 1825 ; and on September the 

 15th, 1826, after a lapse of fifteen months, they were examined. The seals 

 were unbroken, and the bottles were found exactly as they were left, the 

 mercury still being higher on the inside than the outside. One of them 

 was taken to the mercurial trough, and parts of its gaseous contents trans- 

 ferred. Upon examination it proved to be common air, no traces of the 

 original mixture of oxygen and hydrogen remaining in the bottle. A 

 second was examined in the same manner; it proved to contain an explo- 

 sive mixture. A portion of the gas introduced into a tube with a piece of 

 spongy platina, caused dull ignition of the platina. No explosion took 

 place, but a diminution to rather less than one half. The residue support- 

 ed combustion a little better than common air. It would appear, therefore, 

 that nearly a half of the mixture of oxygen and hydrogen had escaped 

 from it, and been replaced by common air. The third bottle, examined 

 in a similar manner, yielded also an explosive mixture, and upon trial, 

 was found to contain nearly two-fifths of a mixture of oxygen and hydro- 

 gen, the rest being very little better in oxygen than common air. 



There is no good reason for supposing that this capability of escape be- 

 tween glass and mercury is confined to the mixture here experimented 

 with ; probably every other gas, having no other action on the mercury or 

 the glass, would have made its way out in the same manner. There is 

 every reason for believing that a small quantity of grease round the stop- 

 pers would have made them perfectly tight. — Quarterly Journal of Science. 



19. On Sementims lodous Acid. By F. Wohler. — From a recent 

 examination of the iodous acid of M. Semen tini, prepared by distill- 

 ing iodine with an equal weight of the chlorate of potassa, M. Wohler 

 finds that this compound does not consist of iodine and oxygen, but 

 of iodine and chlorine; that it is a chloride of iodine similar to that de- 

 scribed by Gay-Lussac. In order to demonstrate the presence of chlo- 

 rine, M. Wohler saturated the liquid obtained by Sementini's method 

 with carbonate of soda, during which a quantity of iodine was separated. 

 The solution was evaporated to dryness, the saline mass heated to redness, 

 taken up in water, and then allowed to crystallize. A number of crystals , 

 were thus procured, which had all the characters of those of common salt. 

 On dissolving them in water, and adding the nitrate of silver, the yellow 



