APPLIED MECHANICS. 



[WRIGHTS AND MEASURES. 



1. To reduce 37 -48262 Ibs. to kilogrammes. 



Div'.dmg by 2-20080) 



17 kilogrammes. 



The reduction may be effected with sufficient accuracy 

 by the following artifice : 



Add together one-third of the given number of Ibs , 

 one-third of that third, and one-twelfth of the last 

 third.* 



Example 2. To reduce 37 -48262 Ibs. to kilogrammes. 



one-third 12 4!U2l 

 one-third of one third 4-16473 

 one-twelfth of the last -34706 



17-00600 



Ejcample a To reduce 5 cwte. 2 qrs. 12 Ibs. to Frenth 

 weight. 



22qra. 

 28 



3)628 Ibs. 



3)209-33 



12) 69-77 



681 



284-91 kilogrammes. 



LINEAL MEASURE!), 



Winches -1 Foot 6 Feet =1 Fathom 



3 Keet -1 Yard 



61 Yards - 1 Pole or Rod 7 '92 Inches = 1 Link 



40 Poles 1 Furlong 100 Links =1 Chain 



8 Furlgs. =1 Mile 80 Chains 1 Mile 



The measures employed for the smaller dimensions of 

 mechanical work, are the foot, its twelfth part the inch, 

 and the fractional divisions of the inch, dividing succes- 

 sively by 2 ; viz. the half, the quarter, the eighth, the 

 sixteenth, the thirty-second, <tc. For larger works, as 

 cuttings, embankments, shafts of mines, and the like, the 

 yard of 3 feet, or the fathom of 6 feet, are the ordinary 

 units. For surveying purposes, the chain of 11 fathoms, 

 or 22 yards, or 66 feet, or 100 links is the unit. And for 

 greater dimensions, the mile, or 1760 yards, or 5280 feet, 

 and its fractional divisions by 2, the half-mile, the quarter 

 mile, the eighth of a mile or furlong, are employed. 



The nautical mile or knot measures 6080 feet 



The unit of French measure is the metre, which is 

 equal in length to 39-371 English inches, or about 3-281 

 English feet, or 3 feet 3| inches very nearly. 



To reduce French measure to English. 



Rule. Multiply the number of French metres by 3, 

 and take the product as so many English feet, so many 

 inches, and so many eighths of inches ; or add together the 

 product, its twelfth part, and the eighth part of the 

 twelfth, for the value in English feet 



Example 1. To reduce 53 metres to English measure. 



ft. in. 



63X3- 169 



169 inches- .... 13 3 

 169 eighths of inches . 1 7} 



173 10J nearly. 



Example 2. To reduce 42 kilometres to English 

 miles. The kilometre is 1000 metres, and 42 kilo- 

 metres are therefore equivalent to 42000 metres. 



Tb* rtMoo of tbb rale b ttii> follow-off : 



One-third of 1. cipraMrd drtimllr, b . . . . -8M3 Ac. 



OM-thM of U. *e.. txptMed lUclmallr, b . -1111 



' if -111, fte., uprttwd dedmallr, b . -OOtl 



Tbrlrram -4SM 



to * DMT approximation to ... -4 J3ii 



43000 



Multiply by 3 



One-twelfth 

 One-eighth 



12GOOO 

 10500 

 13125 



One mile contains 6280)137812-5 feet 



26 '1 miles nearly. 



1 kilometre is exactly 1093-6389 yards. 

 1 mile is exactly 1760 yards. 



Therefore, to reduce kilometres to miles, multiply 



by or -621386. 



For rough calculations, take f ths decimally, -625. 



1760 

 To reduce miles to kilometres, multiply by 



or 1 60931 nearly. 



For rough calculations take l}th decimally, 1 '6. 



The French pied or foot, is equal to 1 -09 English foot 



The French pouce, or inch, is equal to 1'09 English 



inch. 



SUPERFICIAL MEASURE. 



144 square inches = 1 square foot 

 9 square feet = 1 square yard. 

 30i square yards = 1 square pole. 

 40 square poles = 1 rood. 

 4 roods 1 acre. 



The acre, therefore, contains 4840 square yards, or 10 

 square chains, each of 484 square yards. 



The French superficial measure is, for small areas, 

 reckoned by the squares of the metre and its parts, the 

 metre carre, or square metre, being 10765 square feet, 

 or 1-196 square yard. For larger areas, the French unit 

 is the Are, which is a square decametre, or 100 square 

 metres, equivalent to 119 605 square yards. 



SOLID MEASURE. 



1728 cubic inches = 1 cubic foot. 

 27 cubic feet = 1 cubic yard. 

 42 cubic feet = 1 ton of shipping. 

 40 ,, =1 load of rough timber. 

 60 , , =1 load of squared timber. 



The French solid measure is reckoned by the cube of 

 the metre and its parts. 



1 cubic foot = O283 cubic metre. 



1 cubic yard = '7645 ,, 



1 cubic metre = 35 -32 cubic feet 



LIQUID MEASURE. 



There are several varieties of English liquid measure, 

 and provincial variations in their scales ; but the princi- 

 pal unit of liquid measure is the imperial gallon, which 

 contains 277*274 cubic inches, and of which a cubic foot 

 contains 6-2321. or nearly 6Js The unit of French liquid 

 measure is the litre, or cubic decimetre, the thousandth 

 part of a cubic metre, equivalent to 61-028 cubic inches, 

 somewhat less than the imperial quart, which contains 

 09-3185 cubic inches. 



TIME MEASURE. 



60 seconds = 1 minute. I 24 hours => 1 day. 

 60 minutes 1 hour. 7 days = 1 week. 



The French measurement of time is the same. 



TEMPERATURE. 



There are three scales of temperature in use : 



1. Fahrenheit's, used in England, in which the point 

 of water freezing is 32, and the point of water boiling 

 is 212. 



2. The Centigrade, used in France, in which the freez- 

 ing-point of water is the zero, or 0\ and its boiling-point 

 is 100. 



3. Reaumur's, used among some Continental nations, 

 in which the freezing-point of water is zero, or J , and 

 its boiling-point 80. 



