BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [10-] 



Me fore being placed in the hands of ilir hinder the mitering should be carefully 

 examined and any defect in fitting remedied, so thai the glass, when placed in posi- 

 tion, may have accurate bearings on all the sides. The interior of the frame is cov- 

 ered with tin foil, made as smooth as possible lie fore application, to be applied with 

 thoroughly boiled Hour paste (iu which a small proportion of arsenic may be mixed) 

 and rubbed smoothly down till the removal of the blisters, which are apt to appear. 

 The tin foil can be purchased, by weight, at druggists', and the sheets marked off 

 and rut by a rule in strips of proper width, allowing for a trifle of overlapping on 

 the sides. Its cost per volume is merely nominal. 



First-quality single-thick glass for sides must be selected, wholly free from rust, 

 veins, air-bubbles, or any blemish. Such glass can be purchased at 15 cents a pane. 

 The lower glass, after thorough cleaning, especially of its inner surface, with an 

 alkaline wash, and a iinal polishing with slightly wetted white printing paper, is to 

 be tirnily secured in its place by a proper number of tin points; the upper glass is 

 but temporarily fastened. The binder must be directed to cover the exposed sides 

 of the frame with " combed" paper, bringing it over the border of the permanent 

 lower glass and beneath the removable upper glass. 



A B 



FIG. 119. Construction of the Liutner liox. 



The covers of the volume are of heavy binders' board (No. 18), neatly lined within 

 with glazed white paper. On one of the insides of the lids may be attached, by its 

 corners, a sheet with the numbers and names of the species contained in the volume, 

 or these may be placed on the pin bearing the insect. If bound in best quality of 

 imitation morocco, with cloth covers, lettered and gilded on the back, the cost (for 

 a dozen volumes) need not exceed $1 each. If in turkey morocco, it will be $1.50. 



The lettering and ornamentation of the back will vary with the taste of the indi- 

 vidual. The family designations may be permanently lettered, or they may be 

 pasted on the back, on a slip of paper or gum label, as are the generic names, thus 

 permitting the change of the contents of a volume at any time if desired. 



The bits of cork to which the insects are to be pinned are cut in quarter-inch 

 squares from sheet-cork of one-fourth of an inch in thickness. If the trouble be 

 taken to trim oil' the corners, giving them an octagonal form, their appearance will 

 be materially improved and much less care will be required in adjusting them on 

 the glass. 



The cement usually recommended for attaching the cork to the glass is composed 

 of equal parts of white wax and resin. My experience with this has not been favor- 

 able, for, after the lapse of a few years, I have invariably been subjected to tin- 

 serious annoyance of being compelled to renew the entire contents of tlm \olmnc. 



