TIDE-PEEDICTING MACHINE NO. 2. 27 



of the horizontal opening in the dial case. Whenever the chain, the 

 machine being set for a station, is in this position, the sum of the 

 harmonic motions of the time pulleys is zerd, and at that instant, as 

 pointed out on the day, hour, and minute dials, the height indicated 

 by the height pointer is a maximum or the height of high water, or a 

 minimum or the height of low water. 



Paper-feeding mechanism. — The paper-feeding mechanism of the 

 curve-tracing apparatus is arranged in the following manner : Upon a 

 mandrel mounted within the dial case in the upper right-hand corner 

 (plates 9 and 12), which can be quickly removed and replaced, is slipped 

 the blank roll of paper holding on a 1-inch wooden core 380 feet of 

 bond paper, 6 inches wide and 0.0024 inch thick. From the blank 

 roll the paper passes around a 1-inch idler roller mounted in the front 

 plate of the dial case, across the face of the latter for a distance of 13 

 inches and around the feed roller, which is provided near each end 

 with 12 fine needle points for engaging the paper, into the interior of 

 the dial case (plate 9), where it is taken up by the receiving roller, to 

 which it has been fastened by entering its end into a narrow slit. 

 The feeding roller is set in motion by a spur gear at the top of the 

 vertical shaft which operates the time pointers. This spur gear, 46 

 teeth, 40 pitch, engages the lower one of two stud gears connected to 

 each other by a ratchet wheel and pawl, the upper one engaging into 

 the spur gear, 46 teeth, at the lower end of the feed roller. The 

 circumference of the feed roller being exactly 6 inches, one revolution 

 of the vertical shaft, which corresponds to 12 dial hours, therefore, 

 feeds 6 inches of paper, or J inch per dial hour. The ratchet and 

 pawl in the stud gear are placed so as to leave the paper at rest when 

 for any reason the machine is turned backward. If desired, the 

 paper feed can be thrown out of action altogether by turning a small 

 miUed head on the ratchet stud gear. A. sprocket wheel with 16 

 teeth, held by adjustable friction to the upper end of the feed roller, 

 drives the receiving roller by means of a chain and an 8-tooth sprocket. 

 The ratio of the sprockets is such as to force the receiving roller to 

 wind up the paper delivered by the feed roller with the tension furn- 

 ished by the retarding friction of the driving sprocket on therfeed 

 roller. The paper exposed on the dial face is kept taut by an ad- 

 justable retarding friction under the mandrel holding the blank roll. 

 The device works smoothly and winds up without hitch the whole of 

 a year's tide curve. To remove the completed roll, the sprocket is 

 lifted off the receiving roller and set upon a pin provided for the 

 purpose; pulhng out a pin at the back of the dial, case permits of the 

 removal of the upper bearing bracket, when the whole can be lifted 

 out and the metal core of the receiving roUer removed from the paper 

 roU. 



