Its mode of 

 action. 



$|46 SEA LOG AND SOUNDING MACHINE. 



at the other end of the registei* is secured another line, e, of 

 sufficient length to extend beyond the eddy of the vessel's 

 wake. 



The finger on the index 1 revolves once while the log moves 

 forward one mile ; that on the index 2 moves once round in 

 going ten miles ; that on the index 3 makes one revolution 

 when the distance sailed is one hundred miles. When the 

 ■machine is to be used, all the fingers of the indices are set 

 to 0, and both register and rotator committed to the water. 

 As the vessel moves foi-ward, the log must follow, and 

 from the obliquity of the vanes it is evident the rotator, 6, 

 must revolve quicker or slower, correspondent to the ship's 

 velocity. This rotatory motion is communicated by the cord 

 c to the universal joint d!, connected with the wheels, which 

 consequently revolve with the rotator and cord, and thus the 

 actual space passed through, in any given time, is registered 

 on the indices. 

 Registers the - Every occasional or momentary acceleration or retardr- 

 sailed^ '^^^"^^ tion of the vessel, from irregularity of wind, or other causes, 

 which are either altogether passed over, or very vaguely 

 guessed at, in general, are accurately registered on this ma- 

 chine, which not only gives the actual rate of sailing, but 

 the actual distance sailed, since the last Inspection. 



A very little reflection will convince any observer of the 

 great superiority of this machine over all others which have 

 been hitherto introduced. 



It may appear rather presumptuous to criticise the la- 

 bours of Smeaton, and many others, whose endeavours were 

 not crowned with complete success : but it is necessary to 

 point out where their plans failed, in order to prove the 

 very superior advantages of Massey's log; for though some 

 of the machines answered their purposes tolerably well un- 

 der certain circumstances, none of them were nearly correct 

 under all circumstances. Some were erroneous when the 

 ship moved less than four miles in the hour, and others 

 became so when the rate was increased, 

 andwhyt In most of the former inventions, the first mover was a 



spiral, or a rotator in the shape of a Y, and was generally- 

 attached to a register kept in the ship; and as it was abso- 

 lutely necessary^ that this first mover should be out of the 



wake 



Former at- 

 tempts have 

 failed. 



