January 12, 1871. ] 



JOUENAl OP HORTICULTUEE AND COTTAGE GABDENEK. 



27 



remember that I only give the result of my experience with 

 one kind o£ boiler and one description of fuel. I do not pre- 

 tend to state that similar results would follow with different 

 materials to work with. I merely give my experience, and how 

 obtained. 



From observation I am disposed to think that if I had to 

 construct another furnace I should make the space greater 

 between the boiler and the firebars ; instead of 7 I would make 

 it 12 or 14 inches, contracting the sides towards the bottom. 

 By this plan, as the fire burnt out, it would drop closer together, 

 and keep burning, instead of going out, as it does in broad- 

 bottomed furnaces. The quantity of fuel consumed would not 



be greater than, probably not so much as in the ordinary way 

 of setting furnaces. 



I remember the old-fashioned circular-bottomed stoves used 

 in bedrooms. As the fuel burnt the fire dropped down closer, 

 and kept bright for a long time; whereas, with the modern 

 broad flat-bottomed stoves, the fuel is soon burnt right out. 

 If something like the principle of these old-fashioned grates 

 were applied to greenhouse furnaces, making them for slow 

 combustion, as great or greater results would be obtained with 

 less trouble and a smaller consumption of fuel. 



Does Mr. Fish think a screw- valve in the fireplace wouldlbe 

 an improvement ? — E. S. 



GROUND LEVELLING AND PRACTICAL GARDEN PLOTTING.— No. 11. 



DRAWING PLANS. 



To draw and transfer/,9. 34 to the ground, form the rectangle 

 A E c D ; draw the diameter lines e f and g n, also the diagonal 

 lines AC and bd; draw the other lines 12, 3 4, &e. (being 

 parallel to either diameter or diagonal lines) ; draw the circle 

 from centre 0, also the arcs as shown in c and d. 



To transfer the figure to the ground, lay a line from a to e, 

 the distance be- 

 ing 41 feet 6 

 inches, also from 

 E to 0, being 

 62 feet ; lay the 

 line from c to d, 

 which is equal to 

 line A E, lay the 

 line from d to a, 

 which is equal to 

 line B c ; insert 

 a stake at each 

 point. Lay the 

 diameter lines e 

 F and G H, insert 

 a stake at each 

 point ; also lay 

 the diagonal 

 lines A cand b d. 

 From the stake 

 at point A mea- 

 sure 2 feet on 

 line A B, insert a 

 peg as at point 1; 

 also from stake 

 A measure 2 feet 

 on line a d, and 

 insert a peg as at 

 point 23. From 

 stake E measure 

 2 feet on line b a, 

 and insert a peg 

 as at point 11 ; 

 also from stake 

 B measure 2 feet 

 on line e c, and 

 insert peg as at 

 point 24. From 

 stake c measure 

 2 feet on line c 

 B, and insert peg 

 as at point 14 ; 

 also from stake c 

 measure 2 feet 

 on line c d, and 

 insert peg as at 

 point 12. From 

 stake D measure 

 2 feet ou line 

 D c, and insert 

 peg as at point 

 2 ; from stake 

 D measure 2 feet 

 on line D a, and insert peg as at point 13. Lay lines con- 

 necting peg 1 2, 11 12, 13 14, and 23 24. On each side of 

 the diameter line E F measure 18 inches, and insert pegs as at 

 points 17 18, 19 20. From the stakes at points e r on each 

 side measure 3 feet 6 inches, and insert pegs as at points 



5 ^ 



Kb. 34. 



15 16, 21 22. Lay lines connecting pegs 15 16, 17 18, 19 20, 

 and 21 22. On each side of diameter line g h measure 

 18 inches, and insert pegs as at points 5 6, 7 8. From the 

 stakes in points g h measure 3 feet inches, insert pegs as at 

 points 3 4, 9 10. Lay lines connecting pegs 3 4, 5 6, 7 8, 9 10. 

 On each side of the diagonal lines A c and e d measure 2 feet, 



as shown : in 

 points c and d ; 

 extend Jline B a 

 to b, which is 



2 feet, insert a 

 peg as at point 

 6 ; extend line d 

 to a, and in- 

 sert a peg as at 

 point a ; lay a 

 line from peg b 

 to the,! peg at . 

 point ; 12, and 

 from the peg at 

 point 1 to the 

 peg at point a. 

 From stakes b 

 and D find corre- 

 sponding points 

 to 6 12 and 1 a ; 

 lay the corre- 

 sponding lines. 

 Extend the line 

 A B to M, which 

 is 4 feet 3 inches, 

 and insert a peg 

 as at point u. 

 From the stake 

 at point B mea- 

 sure 4 feet 3 

 inches on line 

 B A, and insert 

 a peg as at point 

 r. Extend line 

 D to s, which 

 is 4 feet 3 inches, 

 and insert a peg- 

 as at ))oint s. 

 From stake d 

 measure 4 feet 



3 inches on line 

 D c, and insert 

 peg as at point 

 t. Then lay a 

 line from peg r 

 to peg s, and 

 from peg ' t to 

 peg «. From 

 the stakes at 

 points A find 

 the correspond- 

 ing points to r s 

 and f u, and lay 



the corresponding lines. From the centre^ with a string 9 feet 

 6 inches long trace arcs c, c,c,c; reduce the string 2 feet, and 

 trace arcs d, d, d, d, d, d,d,d; reduce the string 3 feet, and 

 trace the circle 9 feet in diameter. Lay lines to the arcs 

 (with pegs as before described), also to the circle, which com- 



3 S JI 7 9 

 Scale 12 feet to the inch. 



