OF TJEEA AjS'D TJEIJs^AET WATEB. 
801 
Atmospheric pressure . — The relation of the production and elimination of urea with 
the barometric elevation is a direct one, so that both rise and fall together. Table III. 
shows this relation in reference to the monthly averages ; so that the month of the highest 
elimination of urea was that of the greatest atmospheric pressure, and that of the least 
elimination was that of the least pressure. There is also an unbroken parallelism in the 
lines as they increase from March to May, decrease in June, increase in September, 
decrease in October, November, and December, and increase in January and February; 
but there is a want of correspondence in July and August. When the year is divided 
into the two seasons already mentioned, the relations of the barometric elevation, tem- 
perature, urea, and urine are as follows : — 
Barometer. Temperature. Urea. Urine. 
Summer 29'762 55 570 55*7 
Winter 29‘658 44 480 51'9 
The barometric relation is not so erident as it would have been had there not been the 
exceptional conditions in July and August ; but it is sufficient to show that it corre- 
sponds with all the other subjects which we have discussed, and that in summer we had 
high atmospheric pressure and temperature, and great ehmination of urea and urinary 
water, with the contrary conditions during the winter. 
The relation of sudden changes of the barometric pressure to the elimination of urea 
is w'ell seen in the following sequence of days (Plate XXXII. fig. 8) : — 
Table XXIX. 
December ... 
11. 
i 
13. 
14. 
15. 
16. 
17. 
18. 
19. 
inches. 
inches. 
inches. 
inches. 
inches. 
indies. 
inches. 
inches. 
inches. 
Barometer 
29‘528 
29-880 
29-981 
30-120 
30-113 
29-811 
29-513 
29-414 
29-289 
grs. 
grs. 
grs. 
grs. 
grs. 
grs. 
gl'S. 
grs. 
grs. 
Urea 
420-3 
445-2 
530-3 
561 
554-3 
526-5 
498-5 
473-1 
401 
The tw’o lines run parallel throughout the wiiole series. The temperature was nearly 
stationary until the 17th, when it fell, and the diminution in the excretion of urea 
became greater. 
M hen the lines of temperature and barometric pressure run parallel, their influence 
over the elimination of urea is increased ; but when they are opposed, their influence is 
lessened. This is showm in the instance on January 2, Avhen, with great diminution of 
temperature, there w'as but slight diminution of urea on the same day, and an actual 
increase on the following day; for the barometer rose from 29'228 inches on the day 
before to 29'918 inches on the same day, and to 30T43 inches on the following day. 
An instance of the relation of high barometric indication and elimination of urea is 
given in the following sequence : — 
Table XXX. 
April 24. 
April 25. 
April 26. 
April 27. 
April 28. 
April 29. 
April 30. 
May 1. 
May 2. 
Barometer (in.) 
Urea (grs.) . 
Urine (oz.) 
29-619 
483-5 
64 
29-812 
535-2 
76 
30-026 
611 
47 
30-120 
565-6 
41 
30-160 
511-9 
29 
30-204 
713-7 
42 
30-273 
684-6 
64 
30-125 
545-7 
35 
29*951 
528-4 
25 
