170 Miscellanies. 
Again, for the longitude of Brown University, Providence, Mr. 
Paine finds, 
™m. s. 
Boston—Providence, 1 22.64 by 40 chronometers. 
do. 1 22.29 by eclipse of May 15th, 1836. 
Mr. Paine’s observations of the eclipse of Sept. 18th have already 
been reported. hose for latitude and regulation of chronometers 
have been stated more at length, in order to furnish examples of the 
method pursued by that gentleman in the chronometric survey of 
Massachusetts, the only work of the kind of much extent hitherto 
performed in this country. Some idea of the labors of Mr. Paine 
may be formed from the fact, that, during its progress, he has been 
under the necessity of making and reducing more than 100,000 ob- 
servations of altitudes of the sun and stars, without any assistance. 
It is proper to add that Mr. Gilliss’s observations, already reported, 
appear to require a subtractive correction of 1.95s._ Thus Mr. Paine’s 
observations eres. 
h. Se 
Sept. 18th, 21 2%, Barraud 151, fast by its own rate, 4-19 20.80 
b 
y comparison with 682 Barraud, 20.91 
‘ 1678 Arnold, 20.89 
> by mean of three chronometers, 19 20.87 
by Mr. Gilliss’s transit observations, 19 22.8% 
Discrepancy, ie. 
Professor Henry read a paper entitled «Contributions to “-Fleetri-_ : 
city and oe, Sage No. 3. On the Phenomena of Electro-dynamic - 
Induction.” Referred to Prof. A. D. Bache, Dr. Patterson, and Dr. 
‘are. 4 
The primary object of the investigation undertaken by the suthor 
was the discovery of induced currents from ordinary electricity, si™-~ 
ilar to those produced by galvanism. Preparatory to this, a new 
investigation was instituted of the phenomena of galvanic induction, | 
and the result of this forms, perhaps, the most important part: of the a 
communication. + 
The first section of the paper refers to the conditions which # in ~ 4 
ence the induction of a current on itself, as in the case of a ‘Jong © 
wire and a spiral conductor. These are shown to ‘depend on the ~ : 
intensity and quantity of the battery current, and on the length, thick- _ : 
ness, and form of the conductor. ee 
The next section examines the conditions necessary to the produc- j 
tion of powerful secondary currents, and also the changes which take 
place in the same, when the form of the battery, and the size and form 
of the conductor are varied. The important fact is shown, that not 
only a current of intensity can be induced by one of ——— bat 
i ba ; 
aa 
