

1) \\hat objections are there to supporting the girders 

 at Uie ends only without the contact pieces at the bolls? (*) Whs* 

 objections MT there to having the girders in contact with the crown 

 plat* of the fire-box throughout their whole length? 



Draw the views shown in fig. 70, and from the right-hand one 







?8 liar Stay for Stram Boibr. -On [+* 



IS one form of tUy for supporting the flat end of a steam hotter it 

 described. Another form of stay for the same purpose U shown in 

 1. is a jH.rtionoftheendof a steam boiler. CD is one 



and of a bar which extends from one end of the boiler to the other.' 

 Hie ends of this bar are screwed, and when the bar is of wrought 

 iron the screwed parts are generally Urger in diameter than the 

 rest of the bar. When made of steel the bar is generally of uni- 

 form diameter throu^'hunt. In the cane of wrooght-iron bar stays 

 the enlarged ends are welded on to the smaller parta. Welding it 

 not so reliable with steel as with wrought iron, v 

 to the following quest the advantage of having 



the screwed part of the bar larger in diameter than the net? 

 y are steel bar stays not generally enlarged at their screwed 



!J U .' 



