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EDUCATIONAL STANDARD REQUIRED BY VARIOUS MARITIME POWERS FOR MASTERS AND MATES.

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100

The percentage of oxygen varies as follows :--
Sea-shore

21 per cent.
Mines

20'50 do, Confined Houses..

20*75 do. Air travels in England in healthy years at the rate of about 44 miles per hour, and in unhealthy years about 34 miles per hour. Each adult inhales a gallon of air per minute, and consumes daily 30 oz. of oxygen. For the conversion of this oxygen a certain amount of food is required-say 13 oz. of carbon for a male and 11 oz. for a female-equivalent to 3lb. and 2 lb. of bread respectively.

THE POWER OF THE WIND.

Figures to denote the Force Description of of the Wind. Wind.

POWER OF THE WIND

Rate of

the Wind as regards a well-conditioned Man-of-War per Hour or First-class Clipper Ship.

in Miles.

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ON

Calm
Light Air
Light Breeze
Gentle Breeze
Moderate Breeze

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2 3 4

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Fresh Breeze
Strong Breeze
Moderate Gale..
Fresh Gale
Strong Gale

o to Just sufficient to give steerage way

3 TO With which the above Ship with all sail set and clean

I to 2 knots.. 11

15

16

3 to 4 full would go in smooth

20 water..

5 to 6

.. 21-25 Royals, &c.

26

30 Single Reefs

and In which she could T.G. Sails.

31 36 just carry in chase Double Reers and full and by Jib, &c. ....

37

44 Triple Reefs, &c.

45 52 Close Reels & Courses 53 60 In which she could just bear close-reefed

8
9

10

Whole Gale

Main Topsail and reefed Foresail 61
Under Storm Staysail

70- 80 Bare Poles

above 80

11
12

Storm
Hurricane

1

с

V

D

F

W

G
H

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FORMULA FOR RECORDING STATE OF THE

WEATHER. B denotes Blue Sky, i.e. clear or u denotes Ugly, with a heavy hazy atmosphere.

appearance of the Cloudy detached

weather. opening clouds.

Visibility of distant Drizzling Rain.

objects.
Fog-FF Thick Fog.

Wet dew,
Gloomy-dk. weather . Dot under any letter, an extra-
Hail.

ordinary degree.
Lightning:

By the combination of these Misty or Hazy-so as letters all the ordinary phenoto interrupt the view mena of the weather may be Overcast-i.e., whole recorded with certainty and sky covered with an brevity. impervious cloud. BCM — Blue sky, with detached Passing Showers.

opening clouds, but hazy round Squally.

the horizon. Rain-continuous rain GV-Gloomy dark weather, but Snow.

distant objects remarkably Thunder.

visible.

L

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FOR

USE OF INSTRUMENTS IN FORETELLING

WEATHER. On Barometer Scales the fol- And the following summary lowing contractions may be use- may be useful generally :ful in North Latitude :RISE FALL

RISE

FALL
FOR
FOR

FOR
N.Ely.

S. Wly. Cold, Dry, Warm, Wet,
N.W.-N.-E. | S.E.-S.-W.
Dry or Less
Wet or More

Less

More
Wind.
Wind.

Wind.

Wind.
Except Wet
Except Wet Except Wet

Except Wet
from
from
from

from N.Eward. N.Eward.

Cold Side. Cold Side. In other Latitudes substitute South or Southward for North, &c.

or

or

Much inequality of atmospheric pressure or temperature, great depression or elevation of the barometer, sudden or rapid alternations, great falls of rain or snow-indicate more or less change, more or less wind, with its usual accompaniments, either in some places only, or throughout an extensive area of hundreds of miles, is not thousands.

Speaking generally, there is far less occasion to give warning of southerly storms by signal than nf northerly, because those from the southward are preceded by notable signs in the atmosphere, by a falling barometer, and by a temperature higher than usual to the season ; whereas, on the contrary, dangerous storms from a polar quarter (N.W. to N. E.) are sometimes sudden, and usually are preceded by a rising barometer, which is often misleading, especially when accompanied by a temporary lull, of perhaps a day or two, with an appearance of fine weather,

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THERMOMETER.

Fahrenheit, Réaumur, and the Centigrade Scales

CNT. FAH

AHR. RMR. CNT. FAHR. RMR. CNT. FAHR. RMR.CNT. Fahr. Rmr.

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184

136

65 149
52 25 77 20

15 5

12 64 147'2

512 24 75'2 19'2 16 3'2 128 63 145'450'4 23 73'4

17 14 62 22

18

144 61 1418 488 21 69-8 16.8

19 22 152 Zero Fahrenheit corresponds with minus 17.78 Centigrade, and minus 14'22 Réaumur.

143.6

49

716

17.6

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WATER.
1 cubic ft. of water = 624lb. = 5 gallons.
1 cubic ft. of sea water = 641b. 67 gallons.
i imperial gallon = volb. =

277

cubic inches.
224 gallons = 20cwt, = 36 cubic feet.
A column of water 12 inches high, rin. square = '4341b.
A similar column, rin. diameter ="341 lb.
I cylindrical foot = 4'9 gallons = 491b.
An inch rainfall = 141 million gallons per square mile.
Current requires minimum fall 1-10th inch per inch.

IMMERSION IN SALT AND FRESH WATER. To find the difference of immersion or draught in salt and fresh water. If from salt to fresh, multiply the draught of salt water by 36, and divide the product by 35. Is from fresh to salt, multiply the draught of fresh water by 35 and divide the product by 36.

Example :-Required the draught of a vessel in fresh water when drawing 2oft in salt water : 20ft X 36 = 720 – 35ft. = 20 5;in.

Table of draughts worked out by the above formula :

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ITO

300

Yards depth.

Yards depth.
Average. Max.

Average. Max.
Atlantic

4,026

7,750
Irish

240 Pacific

710
4,252 9,310 English Channel..
Indian

3,658
6,040 German

96
Arctic
1,690 5.300 Levant

72 Antarctic

3,000

3,950 Adriatic Mediterranean

45 1,476 2,860 Baltic

43 The Southern Ocean below Cape Horn reaches a depth of 5,500 yards, and off Cape of Good Hope, 5,700 yards. The average depth of the Bay of Biscay is 1,200 yards.

BEAUFORT NOTATION, FORMULA, AS USED FOR
INDICATING THE DISTURBANCE OF THE SEA.
o Calm.

5 Rather Rough. 1 Very Smooth

6 Rough. 2 Smooth.

7 High. 3 Slight.

& Very High. 4 Moderate.

9 Tremendous.

SPECIFIC GRAVITY OF DIFFERENT SUBSTANCES.

21

TIME, AT FULL AND CHANGE, WHEN THE FOLLOWING LIGHTSHIPS SWING FROM FLOOD

TO EBB.

NAME OF LIGHTSHIP.

LAT.

LON.

TIME

OBSERVATIONS.

11

I/

51 16

Ow6

h. m. Bahama Bank

54 20

O N14 12 o W11 45 and high water. Calshot

50 48 40 NI 16 45 W 10 25 ist high water.

12 and high water. Cardigan Bay

52 24 30 N 5 0 30 W 10 30

N Carnarvon Bay

53 5 40 N4 44 30 W 10 30 Cockle

52 41 20 N I 46 20 E 10 20 Corton

52 31 30 N t 49 30 E 10 45 (then N.N.E. at 8 Dudgeon.

53 15 O NO 56 O E7 Turns Eastward at 7. East Goodwin

51 13 ONI 36 25 E 9 10 Uncertain. English & Welsh Ground. 51 26 30 N 2 58 o w 6 56 and high water. Galloper

51 45 ONI 55 50 E 12 o Gull

ONI 28 25 E 913 Hasbro

52 58 ON: 36 O E10 301 Helwick

51 31
ON 4 24

and high water. Inner Dowsing 53 19 20 NO 34 20 E 7 o Turns Eastwd. at 7, N.E.

at 9, N.N.W. at 12. Kentish Knock..

51 39 30 NI 41 OBI 20 Slack lasts about 20 min. Leman and Ower. 53 8 30 N 2 O 20 EII 0 Lynn Well .

53 I 25 NO 25 10 E 6 20 Morecombe Bay

53 54 ON 3 31 o w 10 30 2nd high water. Nab

50 42 15 N O 59 25 W 12 o About. Newarp

52 45 ONI 53 O E 10 30 (out from Sheerness. Nore.

51 29 O NO 48 O E12 30 The last 2 hours ebb, sets North Goodwin.

51 19 30 NI 35 20 E 10 13 Uncertain. Outer Dowsing

52 28 15 NI 2 40 E 8 Turns' Eastward at 8, Owers 50 38 35 NO 41 OW 10 35 About.

(then N. at 9. Royal Sovereign 50 42 40 NO 26 50 8 10 45 Swings about 15 mins. bé. Seven Stones.

50 3 50 N 6

4 30 W 5 o and high water. [fore H. W Shambles

50 30 50 N 2 20 OW 10 20 Shipwash

52 I 30 NI 23 O E II 10 Slack lasts about 40 mins. South Sand Head

51 9 12 NI 28 10 E 9 o Uncertain. Spurn

53 34

ONO 13 O E 6 20 Sunk

51 50 40 NI 30 30 E 11 40 Slack lasts abou 40 mins. Tongue

51 29 ONI 19 20 E 12 15 Varne

50 56 10 N I 16 50 E 8 20 Uncertain.

SPECIFIC GRAVITY OF DIFFERENT SUBSTANCES,

COMPARED WITH WATER.

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