Answers to Quertes. 95 
Bacteria, with all their varieties and subdivisions, belong to the 
vegetable world ; the saccharo- and schizo- mycetes, amongst the 
low fungi. VANCOUVER. 
336.—Multiplied Images in Eye of Beetle.—Full informa- 
tion on this subject will be found in a paper by J. D. Hyatt, on 
“Compound Eyes and Multiple Images,” in the Journal of the 
New York Microscopical Society, Vol. 1., No. 2 (Feb., 1885). If 
this be not readily procurable, most of the necessary information 
may be found on referring to Mrs. Ward’s little book on “The 
Microscope,” on page 69.. I may mention that similar images are 
produced by the valves of certain diatoms, the means of observing 
which, I hope, shortly to describe. Geis 2B: 
336.—Multiplied Images in Eye of Beetle-——Remove the 
assemblage of eyes by maceration, spread on a glass slide, and 
dry. If a pointed object, such as a pin, be then held between the 
stage and the mirror, by proper focussing, the image of the object 
will be seen in each of the lenses. Jo AzeHoge: 
336.—Compound Eyes and Multiple Images.—W. T. will 
find a long article on this subject (much too long to quote) in 
Linsglish Mechanic, for March 27, 1885, page 74, by J. D. Hyatt, 
reprinted from Journal of New York Microscopical Society. 
J. W. M. 
337.—Kiching ou Glass.—Designs are produced on glass by 
means of hydrofluoric acid. The glass is coated with wax, and 
the design is traced on it with a sharp-pointed instrument. It is 
then exposed to the acid, either in the form of a gas or in aqueous 
solution. Afterwards the glass is carefully washed to remove all 
acid, and the wax is removed by heat. The marks made through 
the wax will be found to be permanently etched on the glass, the 
acid having eaten into, or etched (German, d@/zez, to corrode) the 
glass. The hydrofluoric acid acts on the silica of the glass, 
yielding gaseous fluoride of silica (which escapes) and water. 
4 HF + $10,=2H,0 + SIF, 
J. A. Hoae. 
337.—Etching on Glass.—Warm the glass, and cover it with 
a mixture of bees’-wax and turpentine, using only sufficient turpen- 
tine to soften the bees’-wax, let it be spread evenly. Draw the 
design with a fine pointed style, then drop hydrofluoric acid on 
with a piece of wood, or a brush ; the glass will have a ground- 
glass appearance where the wax has been removed. 
337.—Htching on Glass.--An easy and effectual way to etch 
glass is by the following process :—First heat the glass evenly in a 
sand-bath, and then rub it over with purified bees’-wax. If the 
glass is hot enough, the wax will melt and be diffused over the 
