Retrospective Criticism, 747 



or applying them to the mouth, I answer, first, that this is 

 a very dirty needless habit, which ought to be avoided ; but, 

 secondly, if it be persisted in, I still apprehend that no ill 

 consequences can arise from the corrosive sublimate, of which 

 the portion required is so very small. As much as would be 

 taken up on the point of a fine penknife, or less than half the 

 quantity that would commodiously lie on a silver penny, is 

 amply sufficient for a pint bottle of ink ; which, after having 

 been so medicated, I have never known to become in the 

 least degree mouldy, either in the bottle, or after it had been 

 poured into the inkstand and exposed to the action of the air. 

 Possibly, a still less quantity than I have mentioned would 

 serve the purpose. A very minute portion of the poison I 

 find also to be equally effectual in preserving paste from 

 mould, when kept in a cup, &c. ; and I have little doubt that 

 it would equally preserve the same cement from the ravages 

 of insects too ; and thus render it a much better material than 

 gum or glue, for the purpose of fastening down dried plants 

 to the paper for a herbarium. I am. Sir, yours, &c. — ^' 

 W. T. Bree. Allesley Rectory, Sept. 12. 1832. t.^ 



A Wo7'k describing the Genera and Species of Insects, 

 (p. 686.) — Tyro is not singular in his desire (p. 686.) for 

 such a work. Is it not a pity that Mr. Griffith has not given 

 at least a list of all the known species of insects under each 

 genus described in his Animal Kingdom P Perhaps, however, 

 it is his intention to do so. — Sigma. Saffron Walden, Essex, 

 Sept. 25. 1832. 



Epeira diadema. (p. 689.) — Professor Weber of Leipzig 

 states that he watched a little spider as it was constructing its 

 web between two trees. The three principal points to which 

 it was attached formed, as usual, an equilateral triangle. The 

 two upper threads were fixed to the trunks of the trees ; but, 

 not finding a point to fix the lower upon, the spider sus- 

 pended from its extremity a little pebble, by way of counter- 

 poise. The pebble^ being heavier than the animal, kept the 

 web perfectly extended. 



Spiders. — A curious paper was lately read at the Paris 

 Academy of Sciences, on the construction of a spider's nest in 

 the earth. This spider is a native of Corsica. The nest is in 

 the form of a well, 2 in. deep and 6 lines in width. The in- 

 terior is lined with fine web, and the top is furnished with a 

 kind of lid, with hinges, which shuts when the insect is in. 

 This lid, which is composed of earth and web, consists of 

 upwards of forty layers. 



The above paragraphs have lain a good while by us : they 

 were cut out of a newspaper (we believe, the Cambridge Chro- 



