HARDWICKE'S S CIENCE-GO SSIP. 



131 



matter causes it to flow evenly from the brush, and 

 to stand up well and form a ring of considerable 

 substance, which is ready for use in a few minutes, 

 without any risk of its spreading or running in. 

 When perfected, it is probable it may be had of 

 Mr. Ackland at so trifling a cost as to render it not 

 •worth any one's while to trouble himself with the 

 " messing " and uncertainty attending the making 

 of it in small quantities. 



When a cell of greater depth is required than 

 can be built up of cement, other substances then 

 come into requisition. One of my earliest and best 

 form of cells was made of metal rings fixed to the 

 glass by the baked japan. A ring of japan was 

 formed and, while wet, the ring was dropped into 

 it,'properly centred, and then put aside for baking. 

 In this way cells of any dimensions may be securely 

 fastened to the glass, provided the latter be perfectly 

 free from greasiness. 



The black japan for baking is an article specially 

 prepared for the purpose, and must not be con- 

 founded with Brunswick black or any other of the 

 black varnishes that dry quickly by mere exposure 

 to the air, as these contain too little body to with- 

 stand the baking, becoming charred and spoiled by 

 the heat, and there is little doubt that much disap- 

 pointment has often arisen from the want of this 

 knowledge, and not having the proper article. A 

 very superior black japan is obtainable at Sher- 

 born's, 321, Oxford-street (a few doors south-west 

 of the Circus) : a half-pint tin can be had for about a 

 shilling, which has been found to answer thoroughly. 

 In the same way the new asphalte, minus the 

 baking, may be used for putting down almost every 

 description of cell, as it is very adhesive, and, if 

 rightly proportioned, is only just one remove from 

 beingbrittle. Itshouldbeallowedto become "tacky," 

 and the cell then dropped upon it and slightly 

 pressed down into its place. I use pieces of plate- 

 glass about one inch square and a quarter of an 

 inch thick to serve as weights, and to keep the cells 

 flat and down upon the glass slide until the cement 

 has become sufiiciently set to retain them without 

 assistance. 



Of whatever material, however, the cells may be 

 <;omposed, it is an essential point not to use any 

 fixing-down cement that will remain indentable by 

 the nail, or can afterwards soften and run in by 

 being varnished exteriorly, nor must it be capable 

 of setting too hard, so as to become brittle and 

 flake off from the glass ; but under any circum- 

 stances, all compositions containing gold-size ought 

 to be scrupulously rejected as being untrustworthy 

 and insecure for this purpose, or, where such may 

 have been used, they ought invariably and at once 

 to be coated exteriorly with some harder varnish, 

 such as shellac in spirit of wine, gum arable, or 

 the isinglass cement. The majority of the bought 

 slides which prove defective may become so through 



two sources, that is, either from insecurely fastening 

 down the cell, so that it does not retain its adhesion 

 to the glass slide, which may arise from shrinkage 

 of the cement, or its becoming too brittle to with- 

 stand the jarring of use or transit; or it may arise 

 from the same evil attending the fixing on of the 

 cover, a point which will be the next to receive 

 consideration. W. Kencely Bkidgman. 



LADYBIRDS. 



AT p. 70 a correspondent asks the meaning o 

 -^ the word " ladybird." It is an abbreviation of 

 "Our Lady's bird" or bug, as it is sometimes 

 written ; bug in this instance being synonymous 

 with beetle, as it is to this day in the United States, 

 where the term bug almost invariably takes the 

 place of beetle. Many a time, when in the States, 

 I have heard that word, so distasteful to us, used 

 in common conversation by refined ladies or gentle- 

 men, who would not for the world have uttered a 

 syllable likely to " ofi'end ears polite." " Oh, what 

 a lovely bug you have there," has been said to me 

 when exhibiting some fresh-caught, prettily-marked 

 beetle. So that, in our country term "lady-bug" and 

 the more slangy " humbug," we have the last faint 

 echo of a word which still holds its own on the 

 other side of the Atlantic. 



Curiously enough the poetical sentiment which 

 placed the Ladybird under the protection of the 

 Blessed Virgin may be traced in other tongues 

 besides our own. Thus in France these little in- 

 sects are known as Betes de la Vierge, Betes a 

 Dieu, Vaches h Dieu. In Germany they are Marien 

 Kafer, Marien Wiirmchen, Gottes SchafHein, Her- 

 gott's Kiihlein ; or Mary's beetles, Mary's worm- 

 lings, God's lambs, the Lord God's little cows," &c. 



Ladybirds, as is well known, are great enemies 

 to the destructive plant-lice; but whether tlieir 

 dedication indicates a corresponding degree of 

 gratitude on the part of the original namers, I 

 know not. Probably this is so. Country folk, 

 with all their crass ignorance, are often shrewd 

 watchers of nature's works ; and though they find 

 it difficult, or more generally impossible, to com- 

 municate the results of their observations, they can 

 "put two and two together" with marked effect in 

 their own minds. 



I have little doubt then, that " ladybird," " God's 

 cow," "Mary's beetle," are but the expression of a 

 fact observed time out of mind by the peasantry of 

 Europe, that these beetles are indefatigable de- 

 stroyers of the mischievous little aphids or plant- 

 lice, which, minute though they are, would, if un- 



* They are also Lady "cows" in some of our counties. 

 Why is this? I suppose from the fact of their often herding 

 together, and from their colour approximating- that of a red 

 cow: hence also the French Vaclies. The " Schaiflein " is 

 probably due to the first of these two reasons. 



