SHI 



According to Leslie's Table (see Atmosphere ) the temperature of Mel- 

 ville Island should have been nearly 36, whereas it is only 1<>- 



o 



Inches. 

 Greatest height of barometer was ......... 30.86 



Least do. 29.W 



SEA, extent of. See Earth. 

 SEASONS, length of. See Earth, elements of. 

 SECANTS, figure of. See Figure. 

 SEMIDIURNAL arcs.See^rcs Semidiurnal 

 SHIPS, tonnage of. 



To find the tonnage of Ships. 



RULE 1 Multiply the length of the keel, taken within the vessel, or 



as much as the ship treads upon the ground, by the length of the midship 

 beam, taken also within, from plank to plank, and that product by half 

 the breadth, taken as the depth; then divide the last product by 94, and 

 the quotient will give the tonnage. 



If the length of a ship's keel be 80 feet, and the midship-beam SO; 

 required the tonnage. Ans. 382.9787 4. tons. 



RULE 2. Shipwrights take the dimensions on the outside of the light 

 mark, as the ship swims, being unladen, to find the content of the empty- 

 ship. But if the measure of the ship be taken from the light mark to her 

 263 



