22 REPORT—1845. 
of nature in America must be a law in Europe; so that every new principle 
here developed is the common property of the scientific world. 
With much respect I remain, yours truly, 
Ex14s Loomis, 
V. Dr. Lamont, Director of the Magnetical and Meteorological Observatory 
at Munich, to Lieut.- Col. Sabine. 
Munich, March 1, 1845. 
My pear S1r,—In reply to the letter addressed to me by the Committee 
of the British Association appointed to conduct the cooperation of the Asso- 
ciation with regard to magnetic observatories, I have in the first place to 
regref, that, with the exception of one volume of the ‘Greenwich Observa- 
tions,’ and the first part of the ‘ Observations on Days of unusual Magnetic 
Disturbance,’ no observations made at the British or colonial observatories 
have come to my knowledge; and though from the dispositions that have 
been made I have no doubt that the results will be found to answer the dif- 
ferent purposes of theoretical investigation, yet I cannot consider myself en- 
titled to express as yet any positive opinion on the subject*. 
The same question however that is now to be decided by the Committee of 
the British Association, viz. whether and in what manner the magnetic obser- 
vations ought to be continued after 1845, I have been for some time consider- 
ing myself with regard to our own observatory, and after a careful review of 
our results, and others that have come to my knowledge, I have resolved on 
the following plan :— 
1. At the end of this year I will give up the present system of two-hourly 
observations, and will make only three or four observations a-day ; the times 
of observation to be disposed in such a manner as will seem most advan- 
tageous for obtaining the daily range and the monthly means. As for the 
term days, they were observed at Munich only to the end of 1842, and then 
discontinued, from the reasons I mentioned in my report to the Academy 
(published in the ‘ Gelehrte Anzeigen’); the same reasons are also mentioned 
in the ‘ Bulletins de I’ Académie Royale de Bruxelles’ (vol. x. p. i. 178). 
2. I will determine the absolute values of the ditferent magnetic elements 
from time to time as has been done hitherto, both in the observatory and its 
immediate vicinity, and will endeavour to extend my observations to other 
parts of the country as far as circumstances will permit. 
3. Investigations respecting the construction of instruments and the methods 
of observation will be continued. It would, in my opinion, be a great advan- 
tage to science, and is also I believe possible, to render the results less liable 
to error and the methods more simple than they now are. 
4. I will endeavour to have the magnetic observatory kept exactly in its 
present state with regard to the instruments and their arrangement, in order 
that, if any circumstance be afterwards found to have influence on the obser- 
vations, the amount may be determined and the results corrected. Causes of 
error might yet be discovered, the effects of which it would be impossible to 
determine, except with the same instrument and in the same place. 
I have given this account of the system I myself intend to pursue, in order 
that the Committee may judge how far it might seem expedient to arrange the 
British and colonial observatories for two or three years to come on a similar 
plan, reducing at the same time the personal establishment to one or two as- 
sistants besides the director. On computing my own observations and those 
* Dr. Lamont’s opinion on this subject is contained in a subsequent letter, No. XVII. 
