232 T. CURTIES AND J. E. INGPEN ON INSECT MOUNTING, 



received, and in some instances the covers were tilted from the 

 uneven thickness of the objects and the avoidance of pressure. 

 This could be remedied in future by the use of cells, and in one 

 case support for the cover was obtained by two slips of thick glass, 

 allowing the free action of the air upon the thick film of balsam, 

 which kept within the limits till hardened. The absence both of 

 air-bubbles and milkiness — even under the searching illumination 

 of the paraboloid, showed how successful were the methods em- 

 ployed, and the preservation of soft parts, as in spiders and 

 aphides, was remarkable. Although the processes described 

 might not be practicable to the full extent in colder climates, 

 they were highly suggestive, and might be the means of preserving 

 many valuable specimens of exotic entomology. The chief points 

 discussed in the paper were — the avoidance of pressure, by which 

 the preservation not only of natural forms but even of characteristic 

 positions and attitudes was insured; the disuse of potash and 

 other solvents, thereby avoiding the deterioration of tissues ; the 

 exposure to a tropical sun, instead of artifical heat for hardening 

 the balsam ; and the careful abstaining from undue manipulation ; 

 all tending to ensure the preservation of the specimens in a 

 natural manner and with a life-like aspect. 



On an Improved Method op Mounting Opaque Objects. 



By T. Charters White, M.R.C.S., F.R.M.S., &c. 



(Read February 27, 1874.; 



We have all, doubtless, at one time or another, been annoyed by 

 the dewy deposit that settles on the under side of the thin glass 

 covering specimens intended to be viewed as opaque objects, and 

 having myself experienced this annoyance, I was induced to adopt a 

 plan which will, perhaps, be acceptable to those who may be troubled 

 with this disfigurement. I have for some time been in the habit of 

 covering such objects in a manner which, while it excludes dust and 

 securely fixes the cover, allows me when necessary to remove the 

 glass and wipe off any exhalation that may have settled on it, and 

 replace it as at first. I have given this method a fair trial, and 

 can therefore confidently recommend its adoption by others. I have 



