160 



Mr. Hassler, and to use the tables founded upon his experiments, for 

 reductions ; otherwise the uniformity of the system would have been 

 destroyed. During the past year, thirty-four gallon measures had 

 been adjusted and compared, completing the part of the work relating 

 to liquid capacity measures. A set of capacity measures had been 

 adjusted and compared for the Ordnance Depai-tment ; repeated com- 

 parisons had been made of the bars used in measuring the base lines 

 of the coast survey. The results would be found in detail in the re- 

 port. 



Professor Bache then referred to the necessity for action by the dif- 

 ferent States to distribute standards to the counties, and thus to intro- 

 duce uniformity in the weights and measures in actual use. 



Professor Bache referred in this connexion to the successful effort 

 of Mr. Saxton to render automatic the Troughton dividing engine im- 

 ported by the late Mr. Hassler, for the workshop of the Coast Survey. 

 The performance of this engine had never been satisfactory. Its use 

 was fatiguing to the operator, and as he governed the action of the 

 machine, irregularities must result. The length of time required to 

 divide a circle, permitted great fluctuations of temperature, and the 

 heat from the body of the workman acted continually as a disturbing 

 cause. The division being made by a tool governed by hand, the 

 cutting was necessarily imperfect. By a simple and effective me- 

 chanism, the engine had been rendered entirely automatic, a wheel 

 turned by a handle giving motion to all the parts. Thus the screw, 

 giving motion to the dividing wheel, was made to play regularly; 

 and as the wheel moved, the cutting tool was raised, and, descending, 

 traced lines of the requisite length for the subdivisions of five or ten 

 minutes, quarter and half degrees, degrees, and ten degrees; and 

 when the circle was completed, was thrown out of gear. The time 

 of dividing a circle was reduced from more than two days, to less 

 than two hours. 



It had been found that the moveable centre of the machine was im- 

 perfect; and this defect remedied, it appeared that the cutting of the 

 teeth upon the dividing wheel was not perfectly uniform. These 

 smaller irregularities were in the course of correction. Each attempt 

 to divide a circle upon the engine had been an improvement upon the 

 preceding one. 



Prot. A. D. Bache having resumed the chair, — 

 Mr. Walker communicated some observations upon the 

 comet discovered by Captain Hiern in the Gulf of Mexico, 



