On M. Ampere’s Rotating Cylinder. A423 
State of the Barometer and Thermometer from the Beginning 
’ of December to the End of February, at Ness, near Reikiavig, 
in Iceland. By Dr. THorsrEinson. (Reduced to English 
Measures and Fahrenheit’s Thermometer.) 
| 
1821.|Barom | Ther. | 1822. |Barom.| Ther. | 1822. |Barom.| Ther. 
Dec. $ 29-75 | 3S , 29-34 
y 4 | 2e 29-84 | 2.1.29 35 
29-90, : 3 | 29-23 
1, 30°15 | 23: 29-07 
30°18 29 05 
30°18 > | 27:99 
30°12) 3: 27:88 
30-08 27 25 
29-32 | 2: 28-70 
29-62 | 2¢ 29-05 
29-68 29-42 
29-63 | 2¢ 2 | 29:32 
29 49 3 | 29-16 
29-438 | 237 29-05 
29-25 | 3: 28-99 
29-23 | 232 29-57 
29:60} 2 28-56 
99-52 | 2: 27-72 
99-05 28-25 
29-15 28-33 
29°34 28-49 
29°78 | 232 23-63 
29°84] : 23 | 2845 
30°05 | 3% 29-66 
30-06 | 2: 29-68 
30-02 | ¢ 26 | 29-60 
30-00 28-76 
29-40 29-1) 
29:13 
28-96 
29-06 
LXXXVIII. On a particular Construction of M. AmMpernr’s 
Rotating Cylinder. By Mr. Jamus Marsn, of /¥oolwich. 
Communicated by P. Bartow, Esq. Royal Military Aca- 
demy. ; 
To Dr. Tilloch. 
Dear Sir,— Tue inclosed communication from Mr. Marsh 
relates to one of the most pleasing experiments in Electro-mag- 
netism. In its original form it is due to M. Ampere; but it is 
Vol. 59. No. 290, June 1822. 31 much 
