134 Miscellaneous Intelligence. 



lish. Thus a diamond lens will always magnify very nearly twice 

 as much as a glass one ground in the same tool, while its spherical 

 •and chromatic aherrations are no greater with a given aperture. 

 The lens in question is plano-convex, and was ground in a tool 

 which would have made a glass one of yi^yth inch focus, to which 

 it is precisely similar in size and outward figure : it carries the same 

 aperture also equally well, (only with the peculiarity of magnify- 

 ing twice as much, being very nearly -^^ih inch focus.) Most 

 unfortunately, several flaws have appeared in the stone, which is, 

 moreover, at present imperfectly polished ; it is nevertheless capa- 

 ble of acting very well, and shews the most difficult objects both 

 as a single magnifier, and as the objective glass of a compound 

 instrument ; it has been used with as much as -^oth inch of 

 aperture, and exhibited to many individuals who are perfect judges 

 of these things. Mr. Cornelius Varley (who is exceeded by no 

 man in his skill in working small lenses) proposes to make a lens 

 of diamond in the same tool which would form a glass one of gi^th, 

 inch focus, (being the smallest lens which can well be made,) which 

 will, of course, have a focus of about -j^Qth of an inch. Farther par- 

 ticulars concerning the microscopes mentioned in this notice, may 

 be had by application to the artists who have been here designated, 

 and a full and particular account of each will be given in a work 

 on the microscope, which is preparing for the press. 



2. Capillary Attraction. — M. Gilleron says, " If a capillary tube 

 be introduced into mercury, the metal will remain in the tube below 

 the exterior surface. If then the tube be carefully raised, without 

 taking it out of the mercury, the surface of the mercury in the 

 tube may be raised to the level of that without. Operating very 

 carefully, it may even be raised still higher ; its surface will then 

 become concave, the nature of the curve apparently approaching 

 that of the catenarian curve, which I believe also to be that of 

 liquids which in capillary tubes are raised above the level of the 

 external surface. If then the tube be depressed a little, the convex 

 surface may be again given to the mercury in the tube, without its 

 level being depressed below that of the external portion. It ap- 

 pears to me, therefore, that the surface of liquids in capillary tubes 

 is an accessory circumstance, and has no direct influence on the 

 elevation or depression of the liquid." — Bib. Univ. xxvii. 209. 



S. Embossing on Wood. — A new and ingenious method of emboss- 

 ing on wood has been invented by Mr. J. Straker. It may be used 

 either by itself, or in aid of carving, and depends on the fact that if 

 a depression be made by a blunt instrument on the surface of wood, 

 such depressed part will again rise to its original level by subse- 

 quent immersion in water. 



The wood to be ornamented, having first been worked to its pro- 



