102 
NATURE 
[ Mov. 25, 1869 
the planets? but rather, Why do they move in orbits which 
we know to be ellipses having the sun in one of the foci? 
Hardly had this question been put, when a great genius 
answered it. The immortal Newton told us that the same 
law which regulates the motions of the planets round the 
sun, and that of the moon round the earth, determines 
also the path of a stone thrown by the hand, or the velocity 
of an apple falling from a tree. 
One law was shown to hold throughout, and the expres- 
sion of that law having been obtained, we were easily led 
to the third stage in the development of astronomy. 
The problem was now—from our knowledge of the 
present places and motions of the heavenly bodies, and of 
the laws which regulate these, to determine their future 
places. In fact, the last or prophetical stage of the science 
had now been reached, and accordingly we had’a race of 
prophets who compiled our nautical almanacs, culminating 
in two great prophets—one French and one English—who 
told us where to look for Neptune. 
Thus in the mostcomplete branch of physical inquiry 
there have been three stages of development. We have, 
first, the observational stage, the object of which was to 
discover the real motions of the planets of our system ; 
next, we have the stage of generalisation, assigning the 
mechanical laws regulating these motions ; and, lastly, we 
have the stage of deduction, which, from a knowledge of 
the places and laws of motion of the heavenly bodies, 
predicts their future courses. 
Each of these) stages had its own peculiar difficulty to 
encounter. That in ascertaining the actual motions of the 
heavenly bodies consisted in the fact that our point of view 
is a movable one, and it was only when this had been sur- 
mounted that the true explanation was obtained. Again, 
the difficulty in the generalisation accomplished by Newton 
consisted in recognising that the planets in their orbits 
are subject to the same mechanical laws which regulate 
motions on the earth’s surface, and in ascertaining and 
applying these laws; while, again, the difficulty in the third 
or deductive stage was an analytical one, for it was neces- 
sary to possess a method of analysis sufficiently powerful 
to calculate the motions of a set of bodies mutually 
attracting one another. 
Now these historical facts, connected with the progress 
of astronomy, are of very great value to us, especially with 
reference to those other branches of science not so far 
advanced. We’ have, as it were, given us a standard of 
growth and development, and by measuring the younger 
child against the elder, we may be able to know the exact 
advancement of our latest born, and also the course of 
discipline best calculated to ensure a vigorous growth. It 
is by this astronomical standard that I now wish very 
briefly to measure what has been done in meteorology, 
and during these remarks I may perhaps venture to 
suggest a course of diet and discipline. But here, 
alas! there is little advancement to chronicle: the first 
stage of progress—the observational one—is yet very 
incomplete; for, viewing meteorology as that science 
which treats of the physics of the earth’s surface, 
and more particularly of the atmosphere—its motion, 
and its physical properties, it must be acknowledged 
that these are very imperfectly known. At the same 
time it must be owned, that there are very serious diffi- 
culties in the way of obtaining this knowledge, more and 
greater perhaps than there were in obtaining the true 
motions of the heavenly bodies. 
It is not because, as in astronomy, our point of view 
is a movable one; but rather that we are so mixed 
up with the earth and its atmosphere, and the motions 
of the latter are on so large a scale, that we find the 
greatest possible difficulty in grasping their true im- 
port. We are like a soldier in the midst of a great 
battle, who can give but a very poor and partial account 
of it, attaching, as he does, undue importance to those 
passages of arms with which he is most concerned, and 
ignorant, as he must be, of the general plan of the whole. 
What is wanted is a bird’s-eye view of the atmosphere, 
such as it might appear to the inhabitants of the moon, 
who enjoy peculiar advantages in studying the physical 
features of our earth, just as we do with respect to the sur- 
face of our satellite. But there is another difficulty, at least 
in oceanic regions. Here the scientific worker is very 
much in the same position as the Jews of old when rebuild- 
ing their temple, that is to say, he must work with the one 
hand and fight with the other, especially when there is any 
great commotion going on. 
The commander of a vessel during a cyclone must first 
of all look after his vessel, and then, if he has any time to 
spare, it may be devoted to his barometer and thermometer. 
Indeed, whether on sea or land, the grand and interesting 
phenomena of nature carry in their train so much that is 
overwhelming, that the mind of the observer is not un- 
frequently unfitted for calm investigation. There is still a 
third difficulty, and that is the great improbability (despite 
the perseverance and industry shown by Glaisher and 
other meteorologists) of ever obtaining by observation a 
very complete knowledge of the upper regions of the 
earth’s atmosphere. 
So much for the difficulties in the way of observing, and 
now one word with regard to the instrumental means at 
our disposal. Of late years these have been greatly im- 
proved, and one of the most notable achievements in this 
way is the anemometer of Dr. Robinson, by means of 
which we can record continuously the horizontal velocity 
and direction of the wind. Another is the application of 
photography to meteorological observations, so success- 
fully advocated and extended by the present distinguished 
President of the Royal Society, by means of which we 
obtain a continuous record of the pressure, temperature, 
and hygrometric condition of the air. Again, by means of 
certain electrical appliances due to Sir C. Wheatstone and 
others we may place our instrument, whatever it be, at 
the top of a mountain, or at the bottom of the sea, or in 
some equally inaccessible region, while the record of the 
instrument so placed may be read in the quiet and com- 
fort of our own studies. Thus, instrumentally we are. well 
equipped and rapidly improving, but the observations as 
yet made with complete instruments are very few indeed. 
I come now to a very important point. Has the best 
use been made of the observations already obtained ? 
Of course we all know that there has been a deplorable 
want of co-operation among observers, as well as of 
system in making their observations ; but we may hope 
that, through the meteorological offices and_ societies 
established in all civilised countries of the world, a 
greater amount of method will by degrees be obtained, 
There is, however, something more than all this, and 
