498 Retrospective Criticism. 



contrivance as that adopted by Archimedes for setting fire to the Roman 

 fleet ; but Professor Crivelli, arguing that it would require half an hour to 

 adjust a set of glasses like those described by Buffon, so as to carry fire 

 to the spot where the Roman fleet was placed, showed that it was much 

 more probable that Archimedes had rather made use of an instrument like 

 that invented by himself, which he denominated a conio ustorio, by which 

 the burning of the fleet might have been effected in a moment. Passing 

 over these hypotheses, you will perceive that the cono ustorio of Pro- 

 fessor Crivelli might be efficacious in attaining the object that you have 

 proposed, in the remarks you have appended to Mr. Gauen's communica- 

 tions. Professor Crivelli, in dying, divulged to one of his friends the 

 secret, or rather the rules, for constructing these cones ; but I am sorry 

 to state that the invention is still jealously concealed. — Luigi Manetti. 

 Monza, Feb. 26. 1832. 



Fingers and Toes. (p. 325.) — I observe, in your extracts from the 

 Memoirs of the Caledonian Horticultural Society, a notice of this injury 

 to which most of the cabbage tribe is subject. The insect that causes these 

 malformations is called by entomologists Nedejus contractor. Its attack 

 can only be averted by making the plant offensive to the parent fly; and 

 this, it has been lately discovered, can be done by incorporating with the 

 soil soapboilers' waste, or any other substance of similar alkaline quality. 

 Since this discovery has been made, the price of this waste has risen, in 

 the neighbourhood of London, I am told, from 6d. to 5s. per cart-load. 

 Besides partridges preying on the larvae, I have often seen magpies, crows, 

 and, if I mistake not, even rooks, doing this useful service. — J. M. 



Leaves, which should be deciduous, remaining, although dead, through the 

 Winter, 071 Fruit and other Trees. — At p. 358. it is stated that, in Nor- 

 mandy, children go about with lighted torches of rye straw, " for the pur- 

 pose of burning the lichens, mosses, and dead leaves, on the apple trees." 

 Without offering an opinion on the merits of any mode for removing the 

 persisting dead leaves, it may be safely remarked, that to remove them ismost 

 judicious and desirable. Such dead leaves, on examination, will commonly 

 be found to be but the envelopes of so many clusters of eggs or pupas of 

 insects, which the sunshine of spring will excite to life and voracity, just 

 at the time that the expanding leaves of the trees have become eligible 

 food for their sustenance. — J. D. 



The Power of the Honey Bee to produce a Queen. — Sir, Having seen, by 

 Mr. Huish's remarks (p. 375.), that the Society for the Diffusion of Useful 

 Knowledge has published an account of Huber's experiments on the power 

 of the honey bee to produce a queen from the maggot of a working bee, I 

 wish, for the sake of the memory of Huber, whom I hesitate not to desig- 

 nate the prince of apiarians, to set my humble seal to the truth of that 

 wonderful experiment, having done it, more than once, in the presence of 

 a young man, my then pupil, who was a witness, and assisted me in all my 

 experiments, and who will corroborate all that I shall here advance. It 

 was in the month of May, in the year 1828, that I rendered a stock of 

 bees insensible (so that, for half an hour, I could do what I wished with 

 them) with the puff-ball recommended by Keys, and took from the hive two 

 pieces of comb, filled with the brood of the working bee only, in all its stages, 

 from the egg to the young bee just ready to come forth. These pieces, 

 with a third containing honey and bee-bread, I fixed in a small box with glass 

 sides capable of holding about a quart ; the brood combs being fixed 

 outside next the glass, and the honey-comb in the middle. I then put 

 about half a pint of working bees, only, into the box, and conveyed it to a 

 distant garden for a few days, till the bees had forgotten their old hive. I 

 visited them daily, and then brought them back to my own apiary. The 

 bees had, in the mean while, begun to make a queen, by enlarging a 

 cell till it hung down from the surface of the comb; and, at the usual time, 

 they closed it up. I continued to watch them, I may say, almost hourly ; 



