288 ON DYEING REDS ON COTTON. 



nomenon of Franklin divested of all accessory complication^ 

 there can remain no doubt of its true cause. 

 ^c^alPa - ^ ne y wno frequently carry liquids in open vessels had at 

 plied in com- ' east an obscure perception of this theory. They know by 

 «ion hie. experience, that the liquid is much less liable to be spilt by 



sudden movements, if a light body float on their surface. 

 For this reason water-carriers put a wooden trencher into 

 each of their buckets; aud in vineyards a broom is put on the 

 wine, when it is carried from the press to the cellar in an open 

 wooden vessel. Any motion begun 01' terminated too sud- 

 denly would produce a considerable change of level in these 

 liquids, a wave that would cause them to overflow. This 

 wave is nearly prevented by the existence of the light body, 

 that swims on the liquid ; because all the columns, that ter- 

 minate in this body, find in itan obstacle to their undulatory 

 motion, as they can rise or fall only with this body itself: 

 and as it corresponds to a great number of columns at the 

 same time, and. is urged in opposite directions by different 

 columns, it is a considerable obstacle to them all ; and thus 

 it influences those columns it does not cover, since these 

 cannot undulate separately from the others. 



IX. 



On the Nature of Sheep's Dung, and its use in dyeing Cotton 

 the Red that is called India or Adrianople : by J. B. Vit- 

 alis, Professor of Chemistry at Rouen*. 



l*roce>i for JJ[ j-jj? process followed at present in our manufactories 

 ied/ C ° f° r dyeing cotton red, and which was first brought from the 

 Levant, is composed of a series of operations, each of which 

 requires to be elucidated by chemistry, if we would be cer- 

 tain of obtaining uniform success in this sort of dyeing. 

 Chemical ex- Employed bv government to teach the principles of che- 

 i ; . mistry in all its connexions wnh the useful arts, I thought it 



my duty to pay particular attention to that branch of 



• Abridged from the Jonrn. do Pays, vol. LXVI, p. 153. 



industry 



