1 4 INTRODUCTION. 



grievous chances to which imperfect and variable methods expose 

 them every day. But to attain this end, and, by useful changes, to 

 demonstrate the importance of this work, time and long experience 

 are required. We ought to know, thoroughly, the spirit which pre- 

 sides in all the Chinese works, if we wish to naturalize them among 

 us, and to employ them with certainty, and with success. 



We hope that the advanced state of science in France, will some- 

 times give us the advantage over the Chinese, in the application of 

 their methods. I will quote on this subject an interesting fact, which 

 is found in this translation. The Chinese convinced that the purity 

 and frequent renewing of the air are indispensable to the health of 

 the silk worms, have contrived a system of ventilation, which, though 

 it appears incomplete to us in some respects, yet presents several 

 traces of resemblance to that which we owe to M. Darcet. 



The exterior air is made to enter by tubes, which are placed at 

 intervals,- and which can be opened even with the floor. When 

 the air of the silk room becomes foul, it escapes by small windows 

 made in the ceiling. These same tubes also serve to cool and re- 

 fresh the silk rooms ; they are to be shut when one wishes to ele- 

 vate the temperature. 



Indeed, this system is far from equalling that of M. Darcet,* 

 which unites simplicity to energy, and offers the double advantage 

 of keeping a regular temperature, and of causing the air to circulate 

 in the silk room. But, however imperfect the ventilation practised 

 by the Chinese may appear to us, it nevertheless shows how that in- 

 dustrious nation has made efforts to insure the constant success ol 

 the silk culture. 



I have already tried two Chinese methods, which have given me 



* In establishing, by my desire, a simple and economical system of ventilation, 

 which now bears the name of its Author, M. Darcet has added a new and eminent 

 service to all those for which the arts are already indebted to him. The patriotism 

 and disinterestedness which this learned man has shown on this occasion, cannot 

 be too much praised. 



The Minister of Public Works has had a certain number of models of that appa- 

 ratus executed, which have been transmitted to the Prefects, to be deposited in the 

 archives of those Departments, which were occupied more especially with the 

 manufacture of silks. (C. B.) 



