227 



intermediate tensions at 60°, 70°, &c., and comparing them with ob- 

 servation. The result is given in the foUoM^ing table : — 



Table I. 



50° 

 91-98 

 91-98 



60° 

 148-52 

 148-79 



70° 



232- 22 



233- 09 



75° 



287- 27 



288- 50 



80° 



353- 06 



354- 64 



90° 

 523-71 

 525-45 



100° 



760 



760 



Temp, by mercurial therm. 

 Computed tensions. 

 Observed tensions. 







+0-27 



+0-87 



+ 1-23 



+ 1-58 



+ 1-74 







Difference. 



The same operations were performed with temperatures corrected. 

 The result is given in the following table : — 



Table IL 



50° 



50°-512 



91-98 



91-98 



60° 



60°-481 

 149-03 

 148-79 



70° 



70°-413 

 233-30 

 233-09 



75° 



75^-366 

 288-60 

 288-50 



80° 



80°-310 

 354 60 

 354-64 



90° 



90°-17l 



525-09 



525-45 



100° 

 100 

 760 

 760 



Temp, by mere, therm. 

 Temp, by air-therm. 

 Computed tension. 

 Observed tension. 







-0-24 



-0-21 



-0-10 



+0-04 



+0-36 







Difference. 



It is remarked that the differences in the first table show a distinct 

 curvature with reference to the chord ; while in the second table the 

 accordance with the straight line is as perfect as could be expected. 



With the view of bringing these facts out into higher relief and 

 presenting the deflection to the eye on a scale that should at once 

 be relatively correct and very highly magnified, the author computed 

 six values of h from the observations at 90° and 100°, at 80° and 

 100°, &c., without correcting the temperatures, by the formula 



These are given in the following table ; they are quantities propor- 

 tional to the cotangents of the inclination of the chords to the axis 

 of temperature. 



Table III. 



50° 

 158-854 



60° 

 159-025 



70° 

 159-357 



75° 



159-571 



80° 

 159-816 



90° 

 160-387 



lll°-74 bemp.by merc.ther. 

 165-406 Values of h. 







+0-171 



+0-503 



+0-717 



+0-962 



+1-533 



+6-552jDiff. from h at 50° 



The differences in this table are progressively increasing, and their 

 relation to each other is very nearly that of the corresponding dif- 

 ferences of the inclination of the chords. They are represented by 

 these inclinations in a figure, and, in order to render the divergence 

 from a straight line more manifest, the scale taken is 10° angular 

 measure to the unit of difference, the length of the chords corre- 



