146 Improved Rotary Saw Machine* 



feel into the hold, and its bottom forms a pan into which the 

 cinders falU The floor of the fire room is on this level, and 

 being half above and half below the level of the deck, is 

 open to the air. 



When half full it contains about three hundred gallons, 

 but the fire is in large proportion. The steam appears to 

 form very quickly. The advantage of the conical head is, 

 that instead of being the weakest, this is the strongest part 

 of the boiler, and within rules of computation. 



I am respectfully yours. 



J.L.SULLIVAN. 



Art. XXI — Description of an improved Saw machine with 

 sectional teeth for the purpose of manufacturing staves^ 

 headings and siding ; icilh remarks on the machine^ and the 



lumber manufactured by it ; by Robert Eastman, of 

 Brunsic ichy Ma ine* 



Communicated by Professor Cleaveland, of Bowdoin College. 



Tins machine consists of a frame about twenty four feet in 

 length, and five in breadth ; and a carriage about twelve feet 

 in length, and four in breadth. The carriage travels with iron 

 trucks, grooved on their circumferences, which run upon 

 iron slides bolted to the inner sides of the frame. An iron 

 centre passes through one end of the carriagCj and into the 

 end of the log, and is one of the centres, on which it re- 

 volves. At the other end of the carriage, where there are 

 two cross pieces, is an iron arbor, which receives the circu- 

 lar iron index uith concentric circles of holes drilled at 

 equal distances and corresponding to the different sizes of 

 the logs to be manufactured into staves, heading, or siding. 

 These holes are called the numbers of the index. On the 

 end of the index arbor, inside of the carnage, is a square to 

 receive a dog fitted to it, which is first driven into the end 

 of the log, and then slipped on the square of the index ar- 

 bor, by means whereof the index and log are firmlj con- 

 nected together, and both revolve on the index arbor and 

 centre, which are kept in place by stirrup screws. 



Near the middle of the frame is the main shaft, which is of 

 cast iron, and runs on friction rollers, supported by stands 



