396 



Scientific Intelliyence. 



Nov. 



III. The effect of heat upon the conductibility of liquids was de- 

 termined by heating the intermediate porcelain vessel with a spirit 

 lamp. The following table contains the results : — 



Distilled 

 Water. 



50° F. 4« 



77 7 



1064 10 



131 14 



155| 17 



185 21 



212 27 



Well 

 Water. 



I44"i 4« 



68 8 



99J 13 



I55j 27 



1891 35 



212" 41 



Water saturated 

 with Chloride of 

 Sodium at 41oF. 



Distilled Water, 



holding in solution 



_J_ of Nitrate of 



Silver. 



4P 7 8loi 73« 



8 88i 75 



1101 22 99J 77 



1601 30 11 Of 82 



1894 33 133i 89 



"12 34 r The needU de- 



223J 35 155 j> 3"^^^''"' 



t at 13°, 



^, ^ r It proceeds 



212 ? yo** a"'^ 1 



i mains at 22«. 



The deviation of the needle, which expresses the conducting power 

 of the liquid at different temperatures, is the product of the inital 

 deviation by a certain co-efficient. The latter is easily obtained by 

 means of a co-efficient which may be expressed by ^ Calculating 

 the numbers contained in the preceding table, we obtain the follow- 

 ing deductions : — 



1 . The co-efficient is not a constant number for any of the liquids 

 examined ; the increase of conductibility does not proceed uniformly 

 with the increase of temperature. 



2. When the temperature is raised at first the co-efficient does not 

 vary much for the different liquids; the number is greater in pro- 

 portion to the original conducting power. 



3. The number increases to the middle of the thermometric scale 

 most rapidly for good conductors. 



4. The increase of deviation or conductibility, corresponding to a 

 degree of elevation of temperature, is, at the commencement of the 

 heating, 15' for the first liquid, 22 for the second, 17' for the third, 

 and 40 for the fourth. When the middle of the thermometric scale 

 is obtained, the mean value of the increase of conductibility corre- 

 sponding to a degree of heat is 19 for the second liquid, 23' for the 

 third, 54' for the fourth. At 212o this value is 30 for No. 1, 36' for 

 No. 2, and 6' for No. 3. The same value for the nitrate of silver 

 shews a tendency to diminish at 133"j. 



IV. Marianini demonstrated that the electro-magnetic action of 

 simple electro- motive apparatus, is directly proportional to the surface 

 of these elements. And our author has found that the relation which 

 exists between the conducting powers of different liquids is steady, 

 whatever be the absolute electro-magnetic power of the current. 



V. Matteucci substituted a vessel of wood for the porcelain one, of 

 the same size and form. It was varnished internally, and divided 

 into two equal parts by a thin membrane. Having filled the two 

 compartments with well-water, a deviation of 5** was obtained, by 



