SCIENCE IN RELATION TO THE ARTS. 215 



If to the improvements already achieved could be added an engine 

 of half the weight of the present steam-engine and boilers, and work- 

 ing with only half the present expenditure of fuel, a further addition 

 of 30 per cent could be made to the cargo of an Atlantic propeller 

 vessel no longer to be called a steamer and the balance of ad- 

 vantages in favor of such vessels would be sufficient to restrict the 

 use of sailing-craft chiefly to the regattas of this and neighboring 

 ports. 



The admirable work on the "British Navy," lately published by 

 Sir Thomas Brassey, the Civil Chief Lord of the Admiralty, shows that 

 the naval department of this country is fully alive to all improvements 

 having regard to the safety as well as to the fighting qualities of her 

 Majesty's ships of war, and recent experience goes far to prove that, 

 although high speed and manoeuvring qualities are of the utmost 

 value, the armor-plate which appeared to be fast sinking in public 

 favor is not without its value in actual warfare. 



The progressive views perceptible in the construction of the navy 

 are further evidenced in a remarkable degree in the hydrographic de- 

 partment. Captain Sir Frederick Evans, the hydrographer, and Vice- 

 President of the British Association, gave us at York last year a very 

 interesting account of the progress made in that department, which, 

 while dealing chiefly with the preparation of charts showing the depth 

 of water, the direction and force of currents, and the rise of tides near 

 our shores, contains also valuable statistical information regarding the 

 more general questions of the physical conditions of the sea, its tem- 

 perature at various depths, its flora and fauna, as also the rain-fall, and 

 the nature and force of prevailing winds. In connection with this 

 subject the American Naval Department has taken an important part, 

 under the guidance of Captain Maury and the Agassiz father and son, 

 while in this country the persistent labors of Dr. William Carpenter 

 deserve the highest consideration. 



Our knowledge of tidal action has received a most powerful im- 

 pulse through the invention of a self-recording gauge and tide-pre- 

 dicter, which will form the subject of one of the discourses to be 

 delivered at our present meeting by its principal originator, Sir Will- 

 iam Thomson ; when I hope he will furnish us with an explanation 

 of some extraordinary irregularities in tidal records, observed some 

 years ago by Sir John Coode at Portland, and due apparently to at- 

 mospheric influence. 



The application of iron and steel in naval construction rendered the 

 use of the compass for some time illusory, but in 1839 Sir George Airy 

 showed how the errors of the compass, due to the influence experienced 

 from the iron of the ship, may be perfectly corrected by magnets and 

 soft iron placed in the neighborhood of the binnacle, but the great size 

 of the needles in the ordinary compasses rendered the correction of the 

 quadrantal errors practically unattainable. In 1876 Sir William Thorn- 



