﻿ACROSS THE PENINSULA OF ISfDIA, 52^ 



The observations were made on the 3d, 14th, and 

 21st of December, at which times the apparent azi- 

 muths of the star were 1°. 47'. 4!^". i°. 47'. 40 4-", and 

 1°. 47'. 40 — ", leaving out the decimals of the se- 

 conds ; and the mean of the angles made with the line 

 and the star at those times was ^*'. 45'. 50", 2**. 45'. 

 20", and 2^ 45'; Av^hich, compared with the apparent 

 azimuth, M'ill give a mean of 57'. 40" nearly N. Eas- 

 terly, which is the angle made b^ the line with the 

 meridian. 



It 



cliain was extended over that space. Then, if the expansion 

 of brass and steel had been the same, the space which measured 



loo-i feet by the brass, when the thermometer stood 



«— 54* X ,00763 n—s4^ K ,00763 

 at 54®, will now measure ^°°-\ ■ ' — °' 



,1—540 X ,00763 

 100 feet ; by reason of the brass having increased — jcet, 



12 



In IDO feet. But since 100 feet of brass expands ,01237 inches for 

 one degree of the thermometer, the space over which the steel chain 

 extended at u° will measure by the brass standard 



"—54" X ,00763 J^^^S X ,01237 ^ 



looH r reet : and, from a parity of 



iz 



reasoning, if »° be not the temperature in which the space is to be 

 measured by the brass standard, but s° which is rherefore the standard 

 temperature. Then the measurement reduced to that temperature will 



«— 54«X ,00763 S—Si^'X ,01237 r -r , « <. 



give 1 00^ feet, if measured at r of 



IZ 



temperature. 



Case 2d. When the standard temperature an^ the temperature of 

 measurement are ioth beLiv the temperature of coincidence. 



First, suppose the chain to be extended on the ground when the 



thermometer is at «° so that 54 — ;/* shall express the number of de. 

 grecs below the temperature of coincidence. Then, if that space be 

 measured by the brass standard at 54" of temperature, it will be 



equal 



