TIDE-PKEDICTING MACHINE NO. 2. 17 



larger radius, so that the pin pressing against it rises and throws 

 the day pointer to the right one day when this portion has passed by 

 or, in other words, the pointer ''jumps" one day. This condition 

 is indicated by a smaller pointer, upon the same center as the former^ 

 pointing to the right of a plate carrying the legend ''Common year." 

 When this small pointer is thrown over to the left or toward the 

 w^ords "Leap year," the day pointer is locked and can nof jump " 

 the 29th of February. (The plates with the legends referred to 

 were not in place when the photograph was taken.) The day dial 

 can be released by loosening the milled head nut immediately above 

 the large dial ring, and quickly moved and clamped to any desired 

 position. 



Connecting shafts. — From the vertical driving shafts within the 

 component frames motion is imparted to the component shafts 

 which run in bearings in the plates forming the frames by means of 

 horizontal intermediate shafts (best seen in plate 12), and two pairs 

 of gear wheels each, excepting in the case of the components Ssa, Mrriy 

 Sa, Msf, and Mf, which move at speeds so slow as to require resort 

 to the use of one pair of gears and a worm screw and wheel. The 

 rear vertical shaft in the rear frame drives 15 and the forward vertical 

 shaft 16 of the 31 components placed in the rear frame. The vertical 

 shaft in the front component frame gives motion to 9 component 

 shafts, 3 of which are duplicates introduced for reasons to be stated 

 further on, which represent the remaining 6 components of the 37 

 provided for. 



The gears in these trains of motion are set in such relation to each 

 other that all the vertical shafts move clockwise when viewing the 

 machine from above and all the component shafts clockwise when 

 viewing the machine from the time side. 



Dimensions of parts. — The exact dimensions of the parts trans- 

 mitting motion from the crank shaft to the various parts of the 

 machine, as traced out in the foregoing are not of general interest, 

 but are here given for the sake of completeness. Diametral pitch 

 is used in designating the sizes of gear teeth, the number of the pitch 

 being the number of teeth per inch diameter. 



Driving crank with throw of 6 inches (plate 8) on crank shaft 

 A-inch diameter. On inner end of crank shaft, spur gear 40 teeth^ 

 24-pitch, A-inch face, to spur-stud gear, 120 teeth, i-inch face, t^ 

 spur gear 120 teeth, on cross shaft §-inch diameter. On same shaft, 

 bevel gear, 72 teeth, 24-pitch, if-inch fac^, to bevel gear, 72 teeth, 

 on lower end of inclined shaft, J-inch diameter. On same shaft, 

 under desk top, bevel gear, 75 teeth, 30-pitch, %-inch face, to bevel 

 gear, 75 teeth, on low^er end of short vertical shaft through desk top, 

 3^-inch diameter. On same shaft, upper end, inside of dial case 

 (plate 9), bevel gear, 75 teeth, 30-pitch, J^-inch face, to bevel gear, 



4503°— 1,5 3 



