66 Lovering and Bond on Magnetic Observations at Cambridge. 
Paris 3.7 Stockholm 3./13 
Brussells 3. 4 London 2, 4 
Berlin 3.7 Dublin 22 
Turin 330 Christiana 3. 56 
Florence 3,3 Gottingen 3.05 
Milan 3. 87 St. Petersburg 3. 8 
Upsal Bi 7 
In 1837, Gauss published his “.4/gemeine Theorie des Erdmag- 
netismus.” This was the first attempt to subject the Problem of the 
Earth’s Magnetism to strict mathematical analysis. The solution 
was embarrassed and complicated, being of the nature of those 
which had already been performed in determining the Figure of the 
Earth and the Tides. It required the use of Laplace’s celebrated 
coefficients, a powerful instrument but difficult of management. Be- 
sides, it labored under the peculiar disadvantage of not being supplied 
with sufficient data derived from observation for calculating with 
precision the value of the constants. The whole developement may 
be found in the original or translated Memoirs of Gauss and a gen- 
eral idea of the analysis can be obtained from the able Article on 
Terrestrial Magnetism in the London “ Quarterly Review” to which 
reference has already been made. What is here called a theory 
makes none or the most general assumptions as to the nature and 
distribution of magnetism in our planet. The investigation, which is 
mathematical throughout, depends at last on ascertaining the val- 
ues of certain constants from observed data. Here the want was 
felt of a complete series of such as were nearly accurate and strict- 
ly comparable. It cannot be entirely relieved until the accomplish- 
ment of the present magnetic enterprise. With insufficient data, 
but the best that the state of science afforded, many of which were 
obtained through the assistance of the German and Russian Mag- 
