524 



NOTES AND QUERIES. 



[No. 240. 



many which he did not see. Mr. Clear, an intelligent 

 entomologist of Cork, kept some of them alive for more 

 than twelve months. Mr. S. Cooper cannot understand 

 whence the continued supply of the grubs was provided, 

 seeing that larva? do not propagate, and that only one 

 pupa and one perfect insect were voided* ; but the 

 simple fact, that most beetles live several years in the 

 state of larva?, sufficiently accounts for this. Their 

 existing and thriving in the stomach, too, will appear 

 the less wonderful from the fact that it is exceedingly 

 difficult to kill this insect ; for Mr. Henry Baker re- 

 peatedly plunged one into spirits of wine, so fatal to 

 most insects, but it revived, even after being immersed 

 a whole night, and afterwards lived three years, f 



" That there was no deception on the part of the 

 woman, is proved by the fact that she was always 

 anxious to conceal the circumstance; and'that it was 

 only by accident that the medical gentlemen, Drs. 

 Pickells, Herrick, and Thomson, discovered it. More- 

 over, it does not appear that, though poor, she ever took 

 advantage of it to extort money. It is interesting to 

 learn that, by means of turpentine in large doses, she 

 was at length cured." 



Edward Peacock. 



Bottesford Moors, Kirton-in-Lindsey. 



VENTILATION. 



(Vol. ix., p. 415.) 

 " Airs from heaven or blasts from hell." 



The mistake which, it is very respectfully 

 ■submitted, the professed ventilationists fall into, 

 and which may be considered the fons et origo 

 malorum, is the notion that foul air rises upwards, 

 and that pure air comes from below ; which is just 

 the reverse of the fact. 



In any room containing animals or vegetables, 

 the air undergoes a change by respiration.. 



Leaving the vegetables to care for themselves, 

 and considering the animals, if such a title may be 

 reverently given to members of the House and 

 others shut up in confined apartments for the 

 benefit of their species, it is obvious that the pure 

 air of heaven must undergo a change by the re- 

 spiratory organs of the members, which change is 

 absolutely necessary to preserve their lives, and 

 each such apartment is a manufactory for con- 

 verting pure into foul air. Its steam-power is 

 seated in the lungs, which, at each inspiration, 

 take up the oxygen (the principle of life and 

 flame) of the air, and at each expiration give out 

 the carbon of the blood, conveyed by the veins 

 from all parts of the body as refuse, and when 

 purged therefrom by oxygen inspired, convert 

 the venous blood into arterial, and bring life out 

 of death. 



* Cooper's edition of Good's Study of Medicine, vol. i. 

 p. 358. 



f Philosophical Transactions, No. 457. 



What, then, becomes of the expired carbon ? 

 The professional ventilationists say it ascends, and 

 they provide mechanically, but not scientifically, 

 accordingly. On the contrary, it finally descends ; 

 and this is the reason why our beds are always a 

 few feet above the floor. If proof is needed, it 

 may be found by applying a candle to the door, 

 slightly ajar, of a room occupied by a few persons, 

 when it will be found that the flame of the candle 

 will point, when held at the lower part of the 

 door, outwards, and at the upper part of the door 

 inwards, showing how the currents of air pass ; 

 and as every one knows carbon to be heavier than 

 air, the lower current is the one charged with 

 carbon. The Grotto del Cane derives its name 

 from the fact, that a dog passing the stream of 

 carbon issuing from the fissure in the rock, dies ; 

 whilst a man walking erect, with his mouth above 

 the stream of carbon, escapes. Our lime-kilns 

 furnish a common example of the fact of the 

 density of carbon compared with atmospheric air. 

 Experiments in proof are constantly exhibited in 

 chemical lectures. 



The practical inference, experto crede, is that 

 holes in the skirting-boards should be made so as 

 to draw off the foul air, whilst the angelic visits of 

 pure air should be sought from above. Bellows, 

 such as are used in diving-bells, with hot or cold 

 air, might be necessary in an extreme case — long 

 debates in the Commons, for example, — which 

 may require extraordinary ventilation. 



T. J. BUCKTON. 

 Lichfield. 



PHOTOGRAPHIC CORRESPONDENCE. 



Histonj of Photographic Discovery. — Without en- 

 tirely agreeing with the opinion expressed to us a 

 few days since, by an eminent scholar and most ori- 

 ginal thinker, that photography was destined to change 

 the face of the whole world ; we have little doubt 

 it is destined to produce some striking social effects. 

 Its history is, therefore, an interesting one, and the 

 following extract from a paper " On some early Ex- 

 periments in Photography, being the substance of a 

 Letter addressed to Robert Hunt, Esq., by the Rev. 

 J. B. Reade, M. A., F.R.S.," from the Philosophical 

 Magazine for May, 1 854, seems, in that point of view, 

 so important, that we have transferred it to " N. & Q." 



" I may assume that you are already aware, from my 

 letter to Mr. Brayley of March 9, 1839, and published 

 in the British Review for August, 1 847, that the prin- 

 cipal agents I employed, before Mr. Talbot's processes 

 were known, were infusion of galls as an accelerator, 

 and hyposulphite of soda as a fixer. 



" I have no doubt, though I have not a distinct re- 

 collection of the fact, that I was led to use the infusion 

 of galls from my knowledge of the early experiments 

 by Wedgwood. I was aware that he found leather 

 more sensitive than paper; and it is highly probable 

 that the tanning process, which might cause the silver 



