A MODEL OE THE SOLAR SYSTEM TO SCALE. 
103 
House, by the corner of Earl Street and Loates Lane, the bottom 
of Derby Hoad, and through High Street station, very nearly to 
Eearnley Street. The orbit of Mars is one of the most elliptical 
of all the planetary orbits. He completes the circuit in 687 days, 
travelling at a rate of 15 miles per second. 
I defer for the present mentioning the group of small planets 
which occupy the space between Mars and Jupiter, and we will 
consider next the orbit of Jupiter. It is elliptical, and would pass 
through Watford Station, through the Orphan Asylum, through 
the gardens of Bushey Hall, across Bushey Station, just south of 
the Rookery, crossing Cassiobridge Hoad close to the lodge in Cassio- 
bury Park, just north of Nascot House, and so back to Watford 
Station. He moves at the rate of 8 miles per second, completing 
the circuit in about 50 days less than 12 of our years. 
Saturn would cross the railway about a quarter of a mile 
south of the Watford end of the tunnel, would pass north of Bushey 
Mill, close to Bushey Grange, through Bushey Tillage close to the 
east end of the Church, across Watford Heath, south of Oxhey 
Hall, by Cassio Bridge, and across Cassiobury Park about a quarter 
of a mile north of the house. Saturn revolves in his orbit in about 
30 of our years, exactly in 10,579 of our days, travelling at the 
rate of 6 miles per second. 
Uranus would pass close to Garston Church and Kytes, 
through the south part of Bricket Wood, close to Munden 
House, through Letchmore Heath, by Hillfield and Caldicott 
House, across Bushey Heath close to Windmill Lane, by Harts- 
bourne across Harrow Weald Common, over Pinner Hill, through 
Oxhey Wood, close to Moor Park House, between Croxley Green 
and Rickmans worth, by Red Heath, close to the H unton Bridge 
mouth of the Watford tunnel, and through Leavesden. He revolves 
in rather more than 84 years at the rate of four miles a second. 
Last of all comes Neptune, and he would pass just south of 
King’s Langley church, half a mile north of Abbot’s Langley, north 
of Bricket Wood, through Colney Street, by Aldenham Lodge and 
Newberries, through Elstree, through Stanmore south of the Church, 
through Pinner Tillage, across the north end of ltuislip Reservoir, 
by Hare field Grove, through Mill End, close to Callipers, and by 
King’s Langley Lodge back to the Church. His period is 165 years, 
travelling at about 3^ miles per second. This, the slowest-moving 
of the planets, moves 200 times faster than an express train. 
We must now retrace our steps a little to consider the group of 
small planets which occupy the space between Mars and Jupiter. 
At the beginning of the seventeenth century a German astronomer 
named Kepler, having an inquisitive and analytical mind, discovered 
and enunciated three laws relating to the planetary movements. 
Although they were discovered then, and were truly laws, the 
reasons for them were not understood till long after, when Newton 
discovered the law of universal gravitation. I am not going to 
enter into the subject of Kepler’s laws now, but there was another 
discovery made by Kepler which led him to make a prophecy. He 
