112 



Professor Calvert on the Action of 



The above experiments were undertaken with the view of 

 throwing some light on what is sometimes observed when fa- 

 brics printed with the above acids are passed over heated cy- 

 linders or plates ; and I deemed it advisable to inquire also 

 into their action when applied to goods which were simply 

 dried in the atmosphere and afterwards steamed, as is often 

 the case in block-printing. For this purpose I prepared two 

 series of experiments similar to those above described, taking 

 care to separate'the specimens, by first wrapping each in paper, 

 and then placing them between folds of white calico. These 

 samples, so arranged, were then submitted respectively for 

 half an hour to steam having 3, 12, and 45 lb. pressure ; and 

 the results, which are contained in the subjoined table, were 

 very surprising, as the fibres were found to be much more 

 injured than when they had been submitted to dry heat. 



Water alone, 



Steam at a Pressure of 



3 1b. 



45 lb. 



Uninjured. 



Uninjured. 



2 p. ct. Tartaric 



Slightly injured. 



Much more injured. 



Acid, 







4 p. ct. Do. . 



Do. 



Do. 



2 p. ct. Oxalic, 



Very much injured. 



Rotten. 



4 p. ct. Do. . 



Rotten. 



Very rotten. 



Gum alone, 



Uninjured. 



Uninjured. 



... 2 p. ct. Tartaric 



Not more injured than 



Slightly injured. 



Acid, 



water + 2 p. ct. tar- 

 taric acid. 





... 4 p. ct. Do. 



Same as 4 p. ct. tartaric 



Injured, but still rather 





acid and water. 



strong. 



... 2 p. ct. Oxalic, 



Rather more injured 

 than water + 2 p. ct. 

 oxalic acid. 



Rotten. 



... 4 p. ct. Do. 



Very rotten. 



Very rotten. 



Starch alone, 



Uninjured. 



Uninjured. 



2 p. ct. Tartaric 



Hardly injured at all. 



Slightly injured. 



Acid, 







... 4 p. ct. Do. 



Very slightly injured. 



Rather more injured. 



... 2 p. ct. Oxalic, 



Not more injured than 

 water + 2 p. ct. oxalic 

 acid. 



Rotten. 



... 4 p. ct. Do. 



Do. 4 p. ct. Do. 



Very rotten. 



Water + \ p. ct. Sulphu- 



Can hardly be handled. 



Not tried. 



ric Acid, . 







... £ p. ct. Do. 



Falls to pieces in the 

 hands. 



Do. 



