On the RespiraHo7i of Atmospheric Air. 51 



Preparation of the Mwdant for Black. 

 Take three parts of the oxide of iron and one part of the 

 oxide of copper : triturate them in a marble mortar, and pour 

 on them the necessary quantity of pyro-Ugneous acid to dis- 

 solve them. Filter the whole to separate the thick parts, 

 and the mordant is made. 



Application of this Mordant in dyeing Black. 



Steep the stuffs intended to be dyed in this mordant thick- 

 eiied at pleasure. Afterwards proceed to the dyeing in the 

 ordinary decoctions made with different dye-woods. The co- 

 lour obtained will be a very beautiful black, and almost un- 

 changeable by all chemical agents. If the black is meant to 

 serve for printing stuff's or cloths, it is thickened very much, 

 and by mixing it with different tinctures of dye-wood, it will 

 form a black equally beautiful and lasting. 



XI. New Experiments on the Respiration of Atmospheric 

 Air, chiefly with respect to the Absorption of Azote and 

 the Respiration of Gaseous Oxide of Azote. By Pro- 

 fessor Pfaff, of Kiel'-''. 



JL he great discoveries in pneumatic chemistry, and the ap- 

 plications, as ingenious as useful, which have been made of 

 those discoveries to explain the phtenomena of the ceconomy 

 of organized beings (above all, of animal oeconomy), and the 

 careful researches of the most distinguished naturalists, have 

 contributed much to clearing up the doctrine of the chemical 

 effects of respiration. There has been a general agreement 

 among physiologists on some of the most essential points of 

 this theory, as well as upon the production of carbonic acid, 

 the employment of oxygen gas, and the production of ani- 

 mal heat which depends on it. But, notwithstanding the 

 zeal of naturalists, there are still some points which are not 

 sufficiently clear; and the want of agreement in the results 

 ot experiments on those points proves that it was necessary 



• From the Annates <^• Citiinie, No. lo"J. 



D 2 to 



