xvi Mr. Pickering’s Eulogy on 
make a spherical body that would have been easily visible at the 
distance of several of the places of observation, there seem to be 
some grounds for the opinion, that by far the greater part of the 
mass continued on its course without falling to the earth. 
In the year 1811 a remarkable comet made its appearance, and 
was the subject of another able memoir by Dr. Bowditch; the 
result of which was, that this, like the comet observed by him in 
1807, was one that had been before unknown to astronomers.* 
The calculations in this case were made with vast labor and per- 
severance, most of which would have been spared, as he himself 
used to observe, if the improved methods of the present day had 
then been known in this country.t 
Another valuable paper of Dr. Bowditch was published in the 
same volume on that important subject, the Variation of the Mag- 
netic Needle ; containing an account of a series of observations 
made by himself in the years 1805, 1808, 1810, and 1811. 
It had been asserted in some publications of that period, that the 
variation had ceased to decrease, and was then rapidly increasing. 
This was stated, particularly in New York, by persons, who, from 
their official situations as public surveyors, were supposed to be the 
most competent judges ; and observations and facts were adduced 
to prove, that this change had taken place between the years 1804 
and 1807. It was said, that the boundary lines of certain towns in 
that State, and the course of a particular turnpike road, had differed, 
in the space of four or five years, between 15’ and 45’ from the 
original surveys; and hence it was inferred, that a material change 
in the variation had actually taken place. 
But Dr. Bowditch remarked, that the facts, as stated, by no means 
warranted the conclusion drawn from them; for, in the observations 
* Mem. Amer. Acad. Vol. III. p. 313. t See Note F, at the end. 
