RES 
R E S 
in 'the eighth, the medium being 2.04; by 
which it appears that the resistance to the 
same body is, in these slow motions, as tire 
2.04 power of the velocity, or nearly as the 
square of it. 
3. The round ends, and sharp ends, of 
solids, suffer less resistance than the flat or 
plane ends, of the same diameter ; but the 
sharper end has not always the less resistance. 
Thus, the cylinder, and the flat ends of the 
hemisphere and cone, have more resistance, 
than the round or sharp ends of the same ; 
but the round side of the hemisphere has less 
resistance than the sharper end of the cone. 
4. The resistance on the base of the hemi- 
sphere, is to that on the round, or whole 
sphere, as 24 to 1, instead of 2 to 1, as 
the theory gives that relation. Also the ex- 
perimented resistance, on each of these, is 
nearly J more than the quantity assigned by 
the theory. 
5. The resistance on the base of the cone, 
is to that on the vertex, nearly as 2 JY to 1 ; 
and in the same ratio is radius to the sine of 
the angle of inclination of the side of the 
cone to its path or axis. So that, in this 
instance, the resistance is directly as the 
sine of the angle of incidence, the transverse 
section being the same. 
6. When the hinder parts of bodies are of 
different forms, the resistances are different, 
though the fore-parts are exactly alike and 
equal; owing probably to the different pres- 
sures of the air on the hinder parts. Thus, 
the resistance to the fore-part of the cylinder, 
is less than on the equal flat surface of the 
cone, or of the hemisphere; because the 
hinder part of the cylinder is more pressed* 
or pushed by the following air than those of 
the other two figures ; also, for the same 
reason, the base of the hemisphere suffers 
a less resistance than that of the cone, and 
the round side of the hemisphere less than 
the whole sphere. 
Resistance of the fibres of solid bodies 
is more properly called cohesion. 
RESOLUTION, in chemistry, &c. the 
reduction of a mixed body into its compo- 
nent parts, or first principles, by a proper 
analysis. 
Resolution, in music, is when a 
canon or perpetual fugue is not written on 
a line, or in one part, but all the voices that 
are to follow the guide or first voice are 
written separately either in score, that is in 
separate lines, or in separate parts, with the 
pauses each is to observe, and in the proper 
tone to each. 
RESPIRATION consists in drawing a 
certain quantity of air into the lungs, and 
throwing it out again alternately. Whenever 
this function is suspended, even for a very 
short time, the animal dies. 
The fluid respired by animals is common 
atmospherical air ; and it has been ascertained 
by experiment, that no other gaseous hotly 
with which we are acquainted, can be sub- 
stituted for it. All the known gases have 
been tried ; but they all prove fatal to the 
animal which is made to breathe them 
Gaseous bodies, as far as respiration is con- 
cerned, may be divided into two classes : 
1. Unrespirable gases; 2. Respirable gases. 
See Air. 
I. The gases belonging to the first class 
are of such a nature that they cannot be 
j drawn into the lungs of an animal at all ; the 
I epiglottis closing spasmodically whenever 
I they are applied to it. To this class belong 
I carbonic acid, and probably all the other 
acid gases, as has been ascertained by the 
j experiments of Pilatre de Rozier. Ammoni- 
| acal gas belongs to the same class ; for the 
lungs ot animals suffocated by it were found 
by Pilatre not to give a green colour to vege- 
table blues. 
II. The ga=es belonging to the second class 
may be drawn into the lungs, and thrown out 
again, without any opposition from the respi- 
ratory organs ; of course the animal is ca- 
pable of respiring them. They maybe di- 
vided into four subordinate classes; 1. The 
first set of gases occasion death immediately, 
but produce no visible change in the blood. 
They occasion the animal’s death merely by 
depriving him of air, in the same way as he 
would be suffocated by being kept under 
water. The only gases which belong to this 
class are hydrogen and azotic. 2. The se- 
cond set of gases occasion death immediate- 
ly, but at the same time they produce cer- 
tain changes in the blood, and therefore kill, 
not merely by depriving the animal of air, 
but by certain specific properties. The gases 
belonging to this class are carbureted hydro- 
gen, sulphureted hydrogen, carbonic oxide, 
and perhaps also nitrous gas. 3. The third j 
set of gases may be breathed for some time j 
without destroying the animal ; but death en- 
sues at last, provided their action is long 
enough continued. To this class belong the 
nitrous oxide and oxygen gas. 4. The fourth 
set may be breathed any length of time with- 
out injuring the animal. Air is the only- 
gaseous body belonging to this class. 
It has been long known that an animal can 
only breathe a certain quantity of air for a 
limited time ; after which it becomes the 
most deadly poison, and produces suffocation 
as effectually as the most noxious gas, or a 
total absence of air. It was suspected long 
ago, that this change is owing to the ab- 
sorption of a part of the air; and Mayow 
made a number of very ingenious experi- 
ments in order to prove the fact. Dr. 
Priestley and Mr. Scheele demonstrated, that 
the quantity of oxygen gas in atmospheric air 
is diminished ; and Lavoisier demonstrated, 
in 1776, that a quantity of carbonic acid gas, 
which did not previously exist in it, was found 
in air after it had been for some time re- 
spired. It was afterwards proved by Lavoi- 
sier, and many other philosophers, who con- 
firmed and extended his facts, that no ani- 
mal can live in air totally destitute of oxy- 
gen. Even fish, which do not sensibly re- 
spire, die very soon if the water in which 
they live is deprived of oxygen gas. Frogs, 
which can suspend their respiration at plea- 
sure, die in about forty minutes, if the water 
in which they have been confined is covered 
over with oil. ] nsects and worms, as Yau- 
quelin has proved, exhibit precisely the same 
phenomena. They require air as well as 
other animals, and die like them if they are 
deprived of it. They diminish the quantity 
of oxygen in the air in which they live* and 
give out, by respiration, the very same pro- 
ducts as other animals. Worms, which are 
more retentive of life than most other ani- 
mals. or at least not so much affected by 
poisonous gases, absorb every particle of the 
| oxygen contained in the air in which they are 
1 4 C 2 ! 
R E S 5/1 
confined, before they die. Mr. Vauquelin’s 
experiments were made on the gryllus viri- 
dissimus, the Umax flavus, and helix po- 
matia. 
The quantity of air respired differs very 
much in different animals. Man and hot- 
blooded animals are under the necessity ol 
breathing constantly ; whereas amphibious 
animals have a certain power over respiration, 
and can suspend the function altogether for 
a limited time. Dr. Barclay has ascertained 
that these animals acquire a much greater 
command over their respiratory organs by 
habit. Fish do not breathe at all, and con- 
sume so little air, that the small portion ot 
it held in solution by the water in which they 
swim is sufficient for them. It appears that, 
the number of respirations made ir. a given 
time differs considerably in different men 
Dr. Hales reckons them at 20 in a minute 
A man on whom Dr. Menzies made experi- 
ments, breathed only 14 times in a minute. 
Mr. Davy informs us that he makes between 
26 and 27 in a minute. »• 
The quantity of air drawn in and emitted 
at every' respiration must differ considerably 
with the size of the man and the capacity ot 
his lungs. Dr. Menzies found that a man 
draws in at a medium 43.77 cubic inchcs ot 
air at every inspiration. Dr. Goodwin has 
concluded, from his experiments, that, after 
a natural expiration, the mean quantity ot 
air which remains in the lungs amounts to 
109 cubic inches ; but Menzies has endea- 
voured to prove that tl\e number ought to 
have been 179. Mr. Davy has ascertained 
that his lungs, after a forced expiration, still 
retain 41 cubic inches of air ; after a natural 
expiration they contain 
1 1 8 cubic inches 
After a natural inspiration 135 
After a forced inspiration 254 
By a full forced expiration after a forced 
inspiration, he threw out 190 cubic inches 
After a natural inspiration 78.5 
After a natural expiration 67.5 
I 1 us now endeavour to trace the changes 
produced by respiration. These are of two 
kinds, namely : 1. The changes produced 
upon the air respired. 2. Changes produ- 
ced upon the blood exposed to this air. Each 
ol these naturally claims our attention. 
1. For our knowledge of the changes pro- 
duced upon the air by respiration, we. are 
chiefly indebted to Priestley, Cigna, Men- 
zies, Lavoisier and Seguin, and Mr. Davy. 
These changes are the following: 1. Part of 
the air respired disappears. 2. It becomes 
impregnated with carbonic acid. 3. It is 
loaded with water in the state of vapour. 
1. From the experiments of Dr. Menzies, 
it follows, that one-twentieth of the air in- 
spired disappears in the lungs. "Phis agrees 
pretty nearly with the experiments made 
with great care by Lavoisier; an account of 
which he was employed in drawing up when 
he was murdered by order of the French 
usurpers of that period. Neither do the 
experiments published lately by Mr. Davy, 
and which appear to have been performed 
with much precision, differ much from those 
of Dr. Menzies. According to Mr. Davy, 
about -jY-th of the air inspired disappears dur- 
ing respiration. 
Concerning the portion of the air which 
disappears, it has hitherto been the general 
