SCIENCE. 
1 66 
born Observatory — a fine instrument constructed by 
the celebrated Repsolds, of Hamburg, and which must 
have few equals in this country. It must be the oc- 
casion of serious regret that such a splendid piece of 
mechanism is put only to the task of the mere deter- 
mination of time, when it is adequate to the deter- 
mination of the exactest sort of fundamental star- 
positions. We may be permitted the hope that the 
creation of a new fund by the citizens of Chicago 
may ere long contribute to the very possible result of 
placing the Dearborn Observatory on a permanent 
footing as one of the first institutions of the kind in 
this country. 
The Royal Danish Academy of Sciences has re- 
cently offered a prize of 320 crowns for the best dis- 
cussion of the theory of the accidental errors of a 
clock. These errors may be divided into two classes, 
those arising from errors in the time observations and 
those depending upon the quality of the clock. These 
latter in turn may be divided into those depending 
upon the irregularities of the rate of the clock and 
those which are independent of the rate. The dis- 
cussion must include a practical method of determin- 
ing the value of each of these kinds of probable errors 
independent of the others. 
AMERICAN ASSOCIATION FOR THE AD- 
VANCEMENT OF SCIENCE, 1880. 
( Continuation of paflers read.) 
ON PATENT LAWS AS A MEANS FOR THE 
ADVANCEMENT OF SCIENCE. 
By Prof. B. S. Hf.drick, of Washington, D. C. 
The proper aim of science was defined to be the making 
of discoveries. The discoverer of a new mineral, a new 
plant,' a new law of nature, or a new world, has no proprie- 
tory right in his discovery. The honor and distinction he 
obtains is his reward. The discovery, then, cannot be the 
subject of a patent. The laws of nature, the properties of 
m'atter, the physical forces, the laws of their generation 
and government, are like the earth, the air, the water, the 
common property of all. Property in the former, as in the 
latter, is created by enactment. But in civilized communi- 
ties the reason for the law is that something has been 
added to what was given by nature. The land has been 
fenced, ploughed, planted, or buildings placed upon it. 
That gives the foundation for proprietory right, and public 
policy requires that this be recognized, and civil, munici- 
pal and common law does this in the case of the land, the air, 
and the water. The patent laws do the same when discoveries, 
the properties of matter, the forces, the laws which govern, 
them, are made to take the shape of useful inventions. The 
invention which the inventor created is secured to 
him as his property for a period at least. But 
note the laws themselves. It is the reflex action of 
the inventor that acts to advance science. Illustrations 
were given by referring to Watts’ steam engine in advanc- 
ing our knowledge of the laws of heat; the telegraph in 
giving an immense development to the source of magnet- 
ism and electricity; and now the telephone and other kin- 
dred inventions serve to push our knowledge into the far- 
thest and outermost borders. The probation given by the 
patqnt laws enable the great host of investigators to carry 
on their researches, and instead of becoming a tax or bur- 
den to the commuity, they help themselves and bear a 
full share of the ordinary burdens of society. Reference 
was made to Wheatstone, Bessemer, Perkin, Graibe, Sir 
William Thompson, and others in Europe, and to Morse, 
Page, Henry, Gale, Bell, Edison, and many other mem- 
bers of our association, men who have greatly advanced 
science, and have received of the rewards which flow from 
the operation of patent laws. 
THE MEAN RATIO OF OXYGEN TO NITRO- 
GEN IN THE ATMOSPHERE. 
By Professor E W. Morley. 
In the afternoon Prof. E. W. Morley presented the fol- 
lowing remarkable conclusions from experiments : When 
the air at a given place is cold and the barometer high, 
there may sometimes be a vertical descent of cold air. 
Samples collected at such times are more likely to 
approach the composition of the upper atmosphere than 
those collected at other times. If there be any cause 
which tends to produce an excess of nitrogen in the upper 
atmosphere, the average per cent, of oxygen in many samples 
collected as mentioned, will be lower than that of other 
samples. Therefore, to determine whether there be any 
difference in the composition of the lower and upper 
atmosphere, Professor Morley collected samples of air 
during each time of unusual cold and high barometer from 
September, 1878 to April, 1879. In 1878 the average 
amount of oxygen in these was 0.16 per cent, below that of 
other samples. In 1879 the average was 0.12 per cent, 
lower. Careful revision fails to detect any source of error. 
Professor Morley was led. therefore, to presume that the 
upper atmosphere, is acted on by a cause tending to re- 
move part of the oxygen, and to pursue the inquiry by 
means of a series of daily analyses in duplicate of air for 
six months, and a comparison of the results of analysis 
with the thrice daily maps of the United States Signal 
Service. He finds a deficiency of oxygen at times, and 
only at the times, when a vertical descent of air at or near 
the place of collection may be inferred with a fair degree 
of probabdity from these maps, and sometimes a deficiency 
when a veriical descent may be regarded as reasonably 
certain. 
MAXIMA AND MINIMA TIDE-PREDICTING 
MACHINE. 
By William Ferrill. 
This machine is merely prospective as yet, and is designed 
to indicate, by means ot indices on its face, the times and 
heights of high and low water for any tide station. These 
have been determined heretofore by means of laborious 
computations. The mathematical principles upon which 
the proposed mactiine is based, and also the internal struc- 
ture of the machine, are both very complex, and no idea of 
them can be conveniently given here. The face of the 
machine is to be 20 inches by 16 inches, and the depth of 
the case 6 or 8 inches. The face contains an hour circle 10 
inches in diameter, and a lunar and solar index turning 
around the same centre with slightly different velocities, the 
one pointing out the lunar time and the other the solar 
time elapsed from the time of an assumed epoch, as the 
first of January. There is also an index moving vertically, 
indicating the heights of high and low water. The machine 
is designed to stand upon a desk, and the power is the left 
hand applied to a crank on the side, leaving the right hand 
free to record the result as read from the face of the machine. 
The crank is turned until the lunar index comes in con- 
junction with the upper or positive end of a needle, also 
in motion, when the solar index indicates the time of high 
water and the vertically moving index the height of high 
water. The same for low water when the lower index comes 
