Intelligence and Miscellaneous Articles. $49 
Feb, 26.—Dr. Lardner on steam communication witli India. 
March 4,—Mr. Fox on a mode of laying out and working oblique 
or askew bridges. (See p. 299 of the present Number.) 
March |1.—Dr. Arnott on warming and ventilating buildings. 
March 18.—Mr. Wheatstone on the means of investigating the 
structure of crystalline bodies by their sonorous vibrations. 
LXV. Intelligence and Miscellaneous Articles. 
ON THE ATTRACTIVE AND REPULSIVE FORCES OF MAGNETS AT 
VERY SMALL DISTANCES. 
Note applicable to the Correspondence between Professor Ritchie and 
Mr. R. W. Fox, (see our last four Numbers,) on the attractive and 
repulsive forces of magnets at very small distances. Extracted by 
a Correspondent from a paper by W. Snow Harris, Esq., F.R.S., 
in the Trans. R.S. Edinburgh, 1831; dated July 1, 1827. 
£ JN the following table are the results of a series of experiments 
with the attracting and repelling poles. The magnets em- 
ployed are indicated by the letters a, b, c, d, e, their dimensions be- 
ing as follows: 
a, A small cylindrical magnet 2 inches long, 0°2 of an inch in dia- 
meter, and similar in every respect to the suspended magnet zx 
[on which its force was exerted ]. 
, 4°5 inches long, and 0-4 of an inch square, 
, 70 inches in length, and 0-7 of an inch diameter. 
, 9:0 inches long, 0:8 of an inch wide, and 0°3 of an inch thick. 
» 14-0 inches long, 1:0 inch wide, and 0°5 of an inch thick. 
D signifies the distance ; whilst the letters a, b, c, d, e are placed 
over the respective forces.” 
Lee 
is) 
; Dissimilar Poles. Similar Poles. 
a | 6b e | d e a bie d e 
4 oh ae 34+ pe | vse] oes 3-4 
Brel os Aae Se 4+ nea iepe Heer etl eae 4° 
mae, ss ieee Gian) Oe Wesel cselpe caret ine |i 
25) . | ne} os 85] 5 eval h tases wes Mec 8+ 
ie Pog (2504 3 13° | 3 1.202 [O19 les Wh 18s 
18) «| .. 3+ | 35+) 165 | & ode freee’) 125/034]! W544 
1G ites e! j}iies 4: AD 4) 21: Hwee [lesen lbemaral| aot 4+) 185 
0 ec 45 5:5 | 23 estas, lespcenll tide 5+ iO; 
MEAN Messiaen 55 — 0-28") | eS | se. | ore | 475), 5'5 2G 
Teed RCo bes WRU ih MD 
1° | 15 | 2. 10° 12: 49° 3 15 Q2- | 7% 9: 33° 
08) 2+) 3+/15: | 21 acre Nea, 2° | 3° !1o- | 11-9] 4a 
06) 4° | 6—|25°-+ 132 ey 3:+:| 5° 114: ,), 14: .| 56° 
05) 6°" | Br 3s", | 40 [4° | 65 15:5) 14-4) 60- 
0°4| 9° rag : Ot U7: aloo te come 
*3/15* | |18° | I vos 
“These experimental results are quite consistent with the opera- 
tions of the inductive influence [before explained]. We immediately 
perceive, by referring to the attractive forces, that the law of the in- 
* At these distances the repulsive force was superseded by attraction, 
