234 Scientific Intelligence. [Sbpt. 



the fraction of a second. In consequence of peace, the intercourse 

 being open with France, many of oar own countrymen and scien- 

 tific foreigners would assist in ascertaining the time sound is tra- 

 velling across that part of the Channel where the opposite coasts 

 are visible from each other. An accurate account of the barometer, 

 thermometer, hygrometer, electrometer, as well as of the weather, 

 should be kept on those days the experiments are made, and such 

 remarks inserted in the journal as may be found expedient. 

 " 1 remain, my dear Sir, yours, 



" Mark Beacfoy." 



VI. Queries respecting Tanning. 



(To Dr. Thomson.) 

 " SIR, 



" There are few arts which have undergone so little improvement 

 as the art of tanning leather. While science has promoted the 

 interests of other arts, it seems that this art has been either neg- 

 lected by it, or that the prejudice of those who are engaged in it 

 has been so deeply rooted that they have not chosen to listen to the 

 voice of experimental philosophy. Whatever have been the results 

 of modern experiments; it will, I think, be allowed, that they have 

 not been communicated in a form sufficiently plain to be applied lo 

 practice by the tanner himself. You will excuse, therefore, the 

 liberty I take in addressing you on this subject; hoping through the 

 medium of your periodical work to obtain some useful information 

 on the subject of my inquiry. Is it possible to apply Mr. Hatchett's 

 artificial tannin to the purposes of tanning leather ? If so, would 

 not the expense of the charcoal and nitric acid be as great, if not 

 greater, than the oak bark now in common use? Does not the use 

 of the lime water injure the subsequent action of the tannin? I 

 am aware that the pigeon's dung acts as a lixivium, and helps to 

 render the lighter skins flexible ; but how is it that this lixivium 

 acts upon the skin ? Some of these questions, you will say, have 

 been repeatedly asked before ; but I have never been able to obtain 

 any satisfactory answers. Fully convinced, as I am, that it is one 

 of vour main studies to render science subservient to the interests 

 and the business of common life, I trust that you will not think me 

 impertinent in laying before you the above questions. Hoping to 

 obtain some information on the subject in your Annals of Philo- 

 sophy, 



" I remain yours respectfully, 



" Devanus." 



The art of tanning has not been so much overlooked by men of 

 science as my correspondent supposes. Not to mention Seguin, 

 who realized an immense fortune by his fortunate discovery of 

 tannin at the commencement of the French revolution, a society of 

 friends of mine in Glasgow expended five or six thousand pounds 



