| No. 1. | No. 2. | No. 3. | No. 4. | No. 5. | No. 6. | |
|---|---|---|---|---|---|---|
| Copper, | 92.89 | 88.51 | 88.22 | 88.05 | 84.08 | 81.19 |
| Tin, | 5.15 | 9.30 | 5.63 | 11.12 | 7.19 | 18.31 |
| Lead, | 1.78 | 2.30 | 5.88 | 0.78 | 8.53 | 0.75 |
| 99.82 | 100.11 | 99.73 | 99.95 | 99.80 | 100.25 | |
| Loss, | 0.18 | ··· | 0.27 | 0.05 | 0.20 | ··· |
| Gain, | ··· | 0.11 | ··· | ··· | ··· | 0.25 |
| 100. | 100. | 100. | 100. | 100. | 100. | |
| Specific Gravity, | 6.37 | 6.23 | 6.77 | 8.27 | 7.75 | 6.16 |
"These bronzes were first carefully qualitatively analyzed, and found to consist of copper, tin, and lead. Zinc, bismuth, antimony, and silver were carefully sought for, but could not be found. It is probable, however, that a minute trace of the last metal, too small to admit of detection, was present, not, however, as an artificial addition to the alloy, but as a natural accompaniment of the lead.
"In the quantitative analysis, a weighed portion of the bronze was digested in nitric acid, which dissolved the copper and lead, and converted the tin into the insoluble white peroxide. This was collected on a filter, carefully washed, dried, and weighed, after the filter had been burned. The filtered solution containing the copper and the lead was then evaporated to dryness along with a portion of sulphuric acid, which converted the lead into the insoluble sulphate of that metal. This was collected on a filter, treated like the oxide of tin, and weighed. The solution of copper which passed through the filter was precipitated by solution of caustic potass added in excess, and kept at the boiling point till the oxide of copper became dark brown. It was then collected on a filter, washed with boiling water, and weighed after the combustion of the filter.
"The number obtained by adding together the quantities of copper, tin, and lead exceeds that of the quantity of bronze taken in the second and sixth analysis. The increase is marked as excess, and is subtracted from the added numbers, so as to reduce their sum to 100. It should probably be deducted from the copper, which in the state of oxide is not easily deprived of the whole of the potass employed to precipitate it, and is liable, moreover, to retain a little moisture even when it appears quite dry. The presence, accordingly, of potass or water, or both, increases the apparent weight of the copper. As the excess, however, amounts in the one case only to 11/10,000th of the weight of the bronze analyzed, and in the other to 25/10,000th of it, it does not materially influence the result, whether as deducted from the entire alloy, or only from the copper."
To this chemical evidence I am able, through the kindness of Mr. Bell of Dungannon, to add the following results of an analysis recently made for him by Professor Davy of portions of two leaf-shaped bronze swords found in Ireland:—
"No. 1.—Very brittle.
| Copper, | 88.63 |
| Tin, | 8.54 |
| Lead and Iron, | 2.83 |
The lead and iron in this alloy are most likely impurities in copper and tin.
No. 2.—Much more malleable.
| Copper, | 83.50 |
| Lead, | 8.35 |
| Tin, | 5.15 |
| Iron, | 3.00 |