A substance, under this name, designed to take the place of terra cotta and plaster of Paris in the manufacture of small ornamental objects, consists of

Albumen............ 10 parts

Magnesium sulphate. 4 parts

Alum.............. 9 parts

Calcium sulphate, calcined............. 45 parts

Borax.............. 2 parts

Water............... 30 parts

The albumen and alum are dissolved in the water and with the solution so obtained the other ingredients are made into a paste. This paste is molded at once in the usual way and when set the articles are exposed in an oven to a heat of 140° F.

Terra Cotta Cleaning

See Cleaning Preparations' and Methods.

Table Showing the Comparison of the Readings of Thermometers.

Celsius, or Centigrade (C). Reaumur (R). Fahrenheit (F).

c.

R.

F.

C.

R.

F.

-30

-24.0

-22.0

23

18.4

73.4

-25

-20.0

-13.0

24

19.2

75.2

-20

-16.0

- 4.0

25

20.0

77.0

-15

-12.0

+ 5.0

26

20.8

78.8

-10

- 8.0

14.0

27

21.6

80.6

- 5

- 4.0

23.0

28

22.4

82.4

- 4

- 3.2

24.8

29

23.2

84.2

- 3

- 2.4

26.6

30

24.0

86.0

- 2

- 1.8

28.4

31

24.8

87.8

- 1

- 0.8

30.2

32

25.6

89.6

     

33

26.4

91.4

Freezing

point of

water.

34

27.2

93.2

     

35

28.0

95.0

0

0.0

32.0

36

28.8

96.8

1

0.8

33.8

37

29.6

98.6

2

1.6

35.6

38

30.4

100.4

3

2.4

37.4

39

31.2

102.2

4

3.2

39.2

40

32.0

104.0

5

4.0

41.0

41

32.8

105.8

6

4.8

42.8

42

33.6

107.6

7

5.6

44.6

43

34.4

100.4

8

6.4

46.4

44

35.2

111.2

9

7.2

4S.2

45

36.0

113.0

10

8.0

50.0

50

40.0

122.0

11

8.8

51.8

55

44.0

131.0

12

9.6

53.6

60

48.0

140.0

13

10.4

55.4

65

52.0

149.0

14

11.2

57.2

70

56.0

158.0

15

12.0

59.0

75

60.0

167.0

16

12.8

00.8

80

64.0

176.0

17

13.6

62.6

85

68.0

185.0

18

14.4

04.4

90

72.0

194.0

19

15.2

66.2

95

76.0

203.0

20

16.0

68.0

100

80.0

212.0

21

16.8

69.8

     

22

17.6

71.6

Boiling

point

of water

Readings on one scale can be changed into another by the following formulas,

in which t° indicates degrees of temperature:                                   '

Réau. to Fahr.

9/4 t° R + 32° = t°F

Réau to Cent.

Cent.to Fahr. 9/5 t0 C + 320 = t° F

Cent. to Réau. 4/5 t° C = t°R

Fahr. to Cent. 5/9 (t°F-32°)=t°C

Fahr. to Réau. 4/9 (t°F-32°)=t°R