Part 20
"The Germans indicate inches by putting two accents after the number; lines, by putting three accents; 27" 3'''85, means 27 inches 3 lines 85 hundredths of a line; more frequently, they give the height in lines, and the preceding number becomes 327'''85."--_Kaemtz._
3. _Rule for finding Diameter of Bore of a Barometer Tube._
"If the maker has not taken care to measure the interior diameter directly, it may be deduced from the exterior diameter. The exterior diameter is first measured by calipers, and, by deducting from this diameter 01 of an inch for tubes from 3 to 5 of an inch in external diameter, we have an approximation to the interior diameter of the tube."--_Kaemtz._
4. WIND SCALES.
Sea Scale. Wind. Land Scale.
---------- ----- ----------- 0 to 3 = Light = 0 to 1 3 " 5 = Moderate = 1 " 2 5 " 7 = Fresh = 2 " 3 7 " 8 = Strong = 3 " 4 8 " 10 = Heavy = 4 " 5 10 " 12 = Violent = 5 " 6
Pressure in Velocity in Pounds (Land Scale). Miles (Avoirdupois) (Hourly).
------------- --------- ----------- 1/2 = 1 = 10 5 = 2 = 32 10 = 3 = 45 21 = 4 = 65 26 = 5 = 72 32 = 6 = 80
5. Letters to Denote the State of the Weather.
_b_ denotes blue sky, whether with clear or hazy atmosphere.
_c_ " cloudy, that is detached opening clouds.
_d_ " drizzling rain.
_f_ " fog.
_h_ " hail.
_l_ " lightning.
_m_ " misty, or hazy so as to interrupt the view.
_o_ " overcast, gloomy, dull.
_p_ " pa.s.sing showers.
_q_ " squally.
_r_ " rain.
_s_ " snow.
_t_ " thunder.
_u_ " ugly, threatening appearance of sky.
_v_ " unusual visibility of distant objects.
_w_ " wet, that is dew.
A letter repeated denotes much, as _r r_, heavy rain; _f f_, dense fog; and a figure attached denotes duration in hours, as 14 _r_, 14 hours rain.
By the combination of these letters, all the ordinary phenomena of the weather may be recorded with certainty and brevity.
EXAMPLES.--_b c_, blue sky with less proportion of cloud. 2 _r r l l t_, heavy rain for two hours, with much lightning, and some thunder.
The above methods of recording the force of wind and state of weather were originally proposed by Admiral Sir Francis Beaufort. They are now in general use at sea, and by many observers on land.
6. Table of Expansion by Heat from 32 to 212 F.
Platinum 00008842 of the length.
Gla.s.s, Flint 00008117 "
" with Lead 00008622 "
Bra.s.s 00018708 "
Mercury 00180180 "
Water 00433200, from 39 to 212 Alcohol 01100 " 32 to 174 Nitric Acid 01100 Sulphuric Acid 00600
7. Table of Specific Gravity of Bodies at 32 F. except water, which is taken at 394.
Water 1000 Alcohol, pure 0791 " proof 0916 Mercury 13596 Gla.s.s 3 to 27 Bra.s.s 78 to 854 Platinum 21 to 2200
Weight of a cubic foot of water, at the temperature of comparison, 62425 lbs. avoirdupois.
The pound avoirdupois contains 7,000 grains.
Air is 81367 times lighter than water.
The linear expansions are the mean values of the results of various experimentalists. The specific gravities are as given in Professor Rankine's _Applied Mechanics_.
8. Important Temperatures. Under the circ.u.mstances of--
Water boiling at 212 Mercury boils at 660 Sulphuric Acid " 590 Oil of Turpentine " 560 Nitric Acid " 242 Alcohol " 174 A Saturated Solution of Salt " 218 Vital Heat 96 Olive Oil begins to solidify 36 Fresh Water freezes 32 Sea Water freezes 28 Mercury freezes -39
9. TABLE OF METEOROLOGICAL ELEMENTS, FORMING EXPONENTS OF THE CLIMATE OF LONDON.
--------------------------------------------------------------------+ 1841
Mean Height of Barometer, reduced to 32 F., at the mean
to
sea-level.
1861.
+--------------------------------------------------
Mean Monthly Range of Barometer.
Months.
+---------------------------------------------
Mean of all the Highest Temperatures.
+----------------------------------------
Mean of all the Lowest Temperatures.
+-----------------------------------
Mean Temperature.
+------------------------------
Mean Temperature of Dew-point.
+-------------------------
Mean Degree of Humidity.
+----------------------
Mean Number of Rainy
Days.
+------------------
Average Rainfall.
+-------------
Average
Amount of
Cloud (10=
overcast).
+---------
Prevalent
Winds.
---------+-------+----+----+----+----+----+--+---+----+---+---------+
Inches.
In.
In.
---------+-------+----+----+----+----+----+--+---+----+---+---------+ January
29932
144
432
337
383
354
89
11
18
77
W. to N.
February
29962
122
447
332
384
344
85
10
16
74
S. to W.
March
29967
123
500
353
417
364
82
10
15
66
N. to E.
April
29907
106
568
386
463
399
79
11
18
61
N. to E.
May
29931
102
644
442
528
455
76
11
21
61
S. to W.
June
29960
089
712
502
592
508
74
11
19
61
W. to N.
July
29970
079
738
532
619
539
76
11
27
69
W. to N.
August
29954
097
728
534
613
541
77
11
24
65
W. to N.
September
29997
095
674
489
569
511
81
12
24
59
S. to W.
October
29860
133
583
437
502
460
87
13
28
69
S. to W.
November
29929
153
493
377
434
401
89
12
24
72
S.W.
December
29979
152
450
355
401
369
89
12
19
74
W.
---------+-------+----+----+----+----+----+--+---+----+---+---------+ Year
29946
116
580
423
492
437
82
133
253
67
--
---------+-------+----+----+----+----+----+--+---+----+---+---------+ 1 2 3 4 5 6 7 8 9 10 11 ---------------------------------------------------------------------
+-----------------------------------------------------+
Sun above the Horizon on Middle Day.
+---------------------------------------------
REMARKS.
---------+-------+---------------------------------------------
Hours.
---------+-------+---------------------------------------------
January
8-1/2
The majority of the nights are frosty.
February
10
10 frosty nights on the average.
March
12
12 ditto ditto ditto.
Strong winds.
April
14
6 ditto ditto ditto.
May
15-1/2
Very rarely frost.
June
16-1/2
Sun attains greatest North Declination, 21st.
July
16
August
14-1/2
September
12-1/2
October
10-1/2
A few frosty nights. Heavy gales.
November
9
11 nights frosty.
December
8
Sun attains greatest South Declination, 21st.
---------+-------+---------------------------------------------
Year
--
---------+-------+---------------------------------------------
12 13
---------------------------------------------------------------+
In the above Table, columns 1 to 10 are results obtained at the Royal Observatory, Greenwich, by J. Glaisher, Esq., F.R.S. The data contained in columns 2 and 10, are deduced from observations extending over the years 1841 to 1855 inclusive, and are copied from Edward Hughes' _Third Reading Book_; the other columns are results of observations made during the twenty years ending 1861. The rest of the information is from Luke Howard's _Climate of London_.
These valuable data indicate the characteristics of the weather in each month in the suburbs of London, and will be found tolerably accurate as indications of weather, and serviceable as standards for comparisons of observed results, at most places in England.
STANDARD WORKS ON METEOROLOGY
SUPPLIED BY NEGRETTI & ZAMBRA.
THE WEATHER BOOK: A MANUAL OF PRACTICAL METEOROLOGY.
By Vice-Admiral FITZROY, F.R.S., M.I.F., &c.
_Price_, 0 15 6
THE LAW OF STORMS, By H. W. DOVE, F.R.S.
Translated by R. H. SCOTT, M.A.
_Price_, 0 10 6
