396 Appendix. 



useful. It was pronounced to be rotten, and what is technically call- 

 ed ^fuzzy,^ and to be unfit even for those operations which are pre- 

 paratory to its being spun into yarn. After being left, however, dur- 

 ing two or three days, in a room without fire, a great change had taken 

 place in its appearance, and it was found on trial to be as capable of 

 being spun into perfect yarn, as cotton employed in the ordinary man- 

 ner. On an accurate trial of the twist which had been spun from it, 

 a hank supported fully an equal weight with a hank of the same fine- 

 ness spun from cotton fresh from the bag. This fact, established by 

 repeated experiment, proves that with the recovery of its hygrome- 

 trical moisture, cotton, which has been heated, regains its tenacity, 

 and becomes as fit as ever for being applied to manufacturing pur- 

 poses. 



Articles of cotton, silk, and wool, after being manufactured, both 

 separately and in a mixed state, into piece goods, for clothing, were 

 next submitted to the same treatment. Among them were several 

 fabrics, which were purposely chosen, of the most fugitive colors and 

 delicate textures. After being exposed three hours to a temperature 

 of 180°, and then left a few hours in a room without fire, they were 

 pronounced, by an excellent judge of the articles who furnished the 

 specimens, to be perfectly uninjured in every respect. Furs and 

 feathers, similarly heated, underwent no change ; and there can be 

 no doubt that if the apparatus had enabled me conveniently to have 

 raised steam of increased density, a temperature above 212° Fah- 

 renheit would have done no injury to the delicate and costly articles 

 submitted to it.* 



II. The most important point to be ascertained, and that on which 

 the utility of the inquiry hinges, is whether a temperature below 212° 

 Fahrenheit is capable of destroying the contagion o^ fomites. The 

 investigation is one of great nicety, and involves considerable difli- 

 cullies. It was entirely out of my power to try the agency of heat 

 on those contagions which propagate the formidable diseases of cho- 

 lera, plague, scarlatina, typhus, fee. The only way, in which I could 

 arrive at an analogical inference respecting the decomposing power 

 of heat over such contagionsj was by determining its effect on some 



* I have since found that most of those fabrics may be raised to nearly 300° Fah- 

 renheit, without injury to their texture. Some dehcate colors, however, especially 

 greens, are then injured. Writing paper begins to turn brown a litlle below (hat 

 temperature; but the ink is not defaced, as it is by the disinfecting agents applied 

 to letters, which reach this couotry from infected places abroad, and which are often 

 sparcely legible. 



