546 Prof. F. Ilosetti's Experimental Researches 



observations of this nature, we ought to regard as pretty con 7 

 cordant. The following are the results : — 



September 28 a=317\L7 



„ 29 a = 328*66 



October 3 a = 329*72 



„ 14 « = 306*96 



„ 21 a=298*96 



December 17 a = 346*70 



„ 22 < z = 354*45 



Mean .... a = 326*08 

 The calculations made for four other days gave for mean 

 value a = 318*7. Thus the mean of eight days was a = 323*4 

 divisions. In order to give an adequate idea of the exactness, 

 I need only remark that, a being represented in divisions of 

 the galvanometer when sixteen Siemens units were introduced 

 into the circuit, one division would correspond to -^ of a 

 degree ; so that the greatest difference between the values of a 

 and the mean value is not more than 3 degrees. 



I wished to find out what values b ought to have in order that 

 the formula should give for a the value which we have just 

 determined. I found that if we subtract 0*08 from each value 

 of b calculated, we obtain a number, b 1 = b — 0°08, which gives 

 satisfactory values for a. Thus, if with the numbers deduced 

 from the curves (Table VIII.), we reckon the value of a by 

 the formula y=ab e v giving to bi the values found for b 

 (Table IX.) minus 0*08, we have values which are not far 

 from the mean, a = 323*4 (see the following Table). 



28th September. 



E. 



y- 



b. 



K 



a =y 



1-4 



2130 



0-835 



0-755 



315 68 



20 



191-2 



0-840 



0-76 



331-03 



26 



1723 



0-865 



0-785 



323-23 



3-2 



1580 



0-900 



0-82 



298-16 



29th September. 



1-4 



206-8 



0-822 



0-742 



31404 



20 



184-8 



0-837 



0-757 



322-49 



26 



1661 



0-872 



0-792 



304-57 



32 



1530 



0-905 



0-825 



283-16 



4-4 



132-7 



0-909 



0-829 



308-59 



21st October. 



1-8 



200-9 



0-831 



0-751 



328-46 



24 



179-8 



0-881 



0-801 



306-25 



30 



166b' 



0897 



0-867 



305-49 



3-6 



156 I 



0-897 



0816 



32315 



42 



1461 



0-896 



0-820 



343-21 



48 



1372 



0-900 



0-814 



355-67 



