Is helping another scientist bring to publication a work on triangulation in the Alps. Comments on JH's idea of suspending an extremely long plumb bob at a particular precipice in the Alps [Foucault pendulum?]. GP does not believe the results would warrant the expense. Comments on the floating collimator [see JH's 1825-1-14], noting that he does not find it very helpful.

Is preparing a paper on planetary perturbations, which GP would like to send to the Astronomical Society for publication. Comments on JH's ideas on the subject of perturbations. Would the paper being in French be a problem? Comments on Henry Kater's method for finding the zero point in his meridian circle.

Pleased that Astronomical Society will publish GP's memoir (in French) [see GP's 1825-5-27]. Adds some comments for clarification on points in paper and makes arrangements for copies of the paper.

Inquires about the arrival of the memoir sent by GP to JH [see GP's 1825-7-28].

Is very concerned because JH's recent letter did not comment on the arrival of GP's memoir [see GP's 1825-10-24]. Comments on printing and arrangements for copies.

Is pleased that GP's memoir has finally arrived in London [see GP's 1825-11-19]. Indicates arrangements for paying for copies. Comments on GP's astronomical observations of the last several years, and on his method of making reductions.

Thanks JH for introducing WR's paper on photometer to R.S.L. council. Sends drawing of instrument and alterations to WR's paper that resulted from improvements in instrument.

Not upset that JH withdrew WR's paper on photometer from R.S.L. Sent similar paper to David Brewster's [Edinburgh Journal of Science] with note on JH's method for finding relative heating power of solar rays. Wants to dedicate WR's book on light and heat to JH.

Announces 2 June meeting of 'Commissioners for more effectually discovering the Longitude at Sea.' Inquired about 'excise,' but sees no reason to wait for Navy Board to act.

Discusses JH's rent at Devonshire Place.

Suggested improvements to John Leslie's photometer.

Missed JH at the R.S.L. meeting. Has some experiments on which he seeks JH's opinion regarding presentation at the Society. Enclosing report.

Still anxious to become a fellow of the R.S.L. Thanks JH for offer. Would like to be elected before end of present session.

Pleased JH liked his paper on differential photometer. Discusses apparatus for experiments on light. Describes some papers he has written and some he is writing.

Clarifies issues discussed in an earlier letter. Discusses whether the project of making meteorological observations will be feasible if the Board of Longitude does not offer financial support. Attempts to arrange a meeting with JH.

Shares JH's doubts whether the Board of Longitude will fund the Teneriffe expedition, the importance of which he again stresses. Cannot personally cover the costs. Thanks JH for his support and praise.

Encourages JH to bring ES's proposal for Teneriffe experiments before the R.S.L. Council.

Clarifies that the six artillery men are at ES's disposal but under JH's command. Agrees to oversee arrival of the rockets. If expenses are to be paid by the Department of Ordinance, a request must be made by the Secretary of the Board of Longitude. Agrees to keep a record of expenses, not including his time spent, which he considers 'public service.'

Reports on his meeting with Charles Bonne and their subsequent failure to see any signals the first night from either Mont Javoul or La Canche. Worries that the distances are too great for measurements so close to the sea. Speaks of similar measurements between Paris and Strasburg.

Reports his 'entire failure' with Charles Bonne to see signals from both La Canche and Mont Javoul on the same night. Tells of moving the telescopes to Tuniers on 1825-7-15. Speaks of similar experiments elsewhere, which also failed. Concludes that distance is not the only factor in distinguishing signals. Plans to visit JH on 1825-7-25.