316 



(Continued from page 296.) 



as practicable. The first lever should be very strong and 

 light, and for this purpose may be made of skeleton form, of 

 considerable lateral dimensions, or rather vertical, the lever 

 being in a horizontal position and acting vertically. The 

 second lever and pulley are very delicate and slender. 



The position of the pulley, as above arranged, enables me to 

 place a dial over it, with an index attached to the projecting 

 shaft of the pulley. 



One solid plate of metal (brass) forms the support and 

 union of all the parts sustaining the rods, levers, and pulley. 

 The lower extremity of the parallel rods being held by 

 springs, may not necessarily have a continuous metallic sup- 

 port from the other parts. 



The second part of the apparatus does not require the nice 

 mechanical precision of the first part ; its purpose being 

 merely to record the indications of the Thermometer. 



The recording portion of the apparatus consists of a train 

 of cylinders carrying a fillet of paper, the axes of the 

 cylinders being parallel with the parallel wires which guide 

 the registering point of the Thermometer. 



One of these cylinders presents the surface of the paper to 

 the registering point, which passes very near, but not in con- 

 tact with it, the movements of the registering point being 

 across the paper. A series of levers and springs, which can- 

 not be well described without diagrams, gives the proper 

 "feed" to the cylinders and paper. But as this part of the 

 apparatus is susceptible of an endless variety of modifications, 

 it is unnecessary to speak of it further. 



Connected with the cylinders is a hammer, made with re- 

 ference to the ividtTi of the fillet of paper. This hammer im- 

 parts the necessary force to the registering point to make a 

 small hole in the paper fillet, and is, when not in action, held 

 from contact with the registering point by means of a recoil 

 spring, which spring is adjustable by means of a screw. The 

 levers connected with the feed of the cylinders are operated 

 by the back movement of the hammer. 



The third part of the apparatus consists of a common ma- 



