| A factitious article is prepared by calcining a mixture of colcothar and red ochre. |
| Emery with oil is used for grinding down, and tin-putty or colcothar for polishing. |
| When this colcothar hath undergone a violent fire, as in the experiment now related, scarce any Acid remains therein. |
| When the cork or wooden disc edged with hat felt is used for polishing, putty or colcothar is applied to it. |
| The wooden disc is also employed for this purpose with putty, colcothar, or washed tripoli. |
