| Top Edge. | Bottom Edge. | ||||||
| Contrac- tion. | Percentage on original length. | Expan- sion. | Percentage on original length. | ||||
| Inches. | Inches. | ||||||
| After | 1st | cooling | .3 | .83 | .05 | .13 | |
| „ | 2nd | „ | .6 | 4 | 1.72 | .12 | .32 |
| „ | 3rd | „ | 1.0 | 2 | 2.75 | .22 | .60 |
| „ | 4th | „ | 1.3 | 8 | 3.72 | .30 | .80 |
| „ | 5th | „ | 1.6 | 2 | 4.37 | .37 | 1.00 |
| „ | 10th | „ | 3.1 | 4 | 8.46 | .76 | 2.05 |
“Experiment No. 12.—Wrought-iron hoop, turned and bored, 6 inches diameter (18.85 inches circumference) outside, by 2 inches deep by .375 inch thick, heated to redness, then cooled, with lower edge barely touching the water (see [Fig. 1437] at b for final form of hoop after twenty heatings and coolings).
| Top Edge. | Bottom Edge. | |||||
| Contrac- tion. Outside circum- ference. | Percentage of original circum- ference. | Contrac- tion. Outside circum- ference. | Percentage of original circum- ference. | |||
| Inches. | Inches. | |||||
| After | 5th | cooling | .10 | .53 | .16 | .85 |
| „ | 10th | „ | .22 | 1.17 | .34 | 1.80 |
| „ | 15th | „ | .32 | 1.70 | .48 | 2.54 |
| „ | 20th | „ | .48 | 2.54 | .62 | 3.30 |
“Experiment No. 13.—Wrought-iron hoop, turned and bored, 6 inches diameter (18.85 inches circumference) outside by 2 inches deep by .375 inch thick, heated to redness, then cooled one-fourth its depth in water (see [Fig. 1437] at c for final form of hoop after twenty heatings and coolings).
| Top Edge. | Bottom Edge. | ||||||
| Contrac- tion. | Percentage of original circum- ference. | Extension. | Percentage of original circum- ference. | ||||
| Inches. | Inches. | ||||||
| After | 1st | cooling | .06 | .32 | .02 | .10 | |
| „ | 5th | „ | .28 | 1.50 | { | A hair’s breadth contraction. | |
| „ | 10th | „ | .56 | 3.00 | { | Returned to original circumference. | |
| „ | 15th | „ | .78 | 4.14 | .02 contraction. | .10 | |
| „ | 20th | „ | 1.12 | 6.00 | .02 contraction. | .10 | |
“Experiment No. 14.—Wrought-iron hoop, turned and bored. 6 inches diameter (18.85 inches circumference) outside by 2 inches deep by .375 inch thick, heated to redness, then cooled one-half its depth in water (see [Fig. 1437] at d for final form of hoop after twenty heatings and coolings).
| Top Edge. | Bottom Edge. | |||||
| Contrac- tion. | Percentage of original circum- ference. | Expan- sion. | Percentage of original circum- ference. | |||
| Inches. | Inches. | |||||
| After | 5th | cooling | .46 | 2.44 | .06 | .32 |
| „ | 10th | „ | .96 | 5.00 | .09 | .48 |
| „ | 15th | „ | 1.34 | 7.10 | .18 | .96 |
| „ | 20th | „ | 1.80 | 9.10 | .26 | 1.38 |
“Experiment No. 15.—Wrought-iron hoop turned and bored, 6 inches in diameter (18.85 inches circumference) outside by 2 inches deep by .375 inch thick, heated to redness, then cooled three-fourths its depth in water (see [Fig. 1437] at e for final form of hoop after twenty heatings and coolings).
| Top Edge. | Bottom Edge. | |||||||
| Contrac- tion. | Percentage of original circum- ference. | Expansion. | Percentage of original circum- ference. | |||||
| Inches. | Inches. | |||||||
| After | 1st | cooling | .05 | .26 | .015 | .08 | ||
| „ | 5th | „ | .30 | 1.60 | .02 | .10 | ||
| „ | 10th | „ | .56 | 3.00 | { | A hair’s breadth contraction. | ||
| „ | 15th | „ | .74 | 3.92 | { | .02 contraction. | } | .10 |
| „ | 20th | „ | 1.02 | 5.40 | { | .03 contraction. | } | .10 |
“Experiment No. 16.—Cast-copper ring, turned and bored to same dimensions as Nos. 12, 13, 14, and 15, heated to redness, then cooled half its depth in water (see [Fig. 1437] at f for final form of hoop after twenty heatings and coolings).