Folio 9: Marginal illustrations showing a reel of conducting wire, the detonator...

Folio 9: Marginal illustrations showing a reel of conducting wire, the detonator and the cylinders in which it is placed. Folio 9: Short description of the effects of charges of between 240 and 2400lbs on the surface of the water above an explosion at 13 fathoms. Fish are killed or stunned by the explosions, sometimes as much as a mile away, but seem to become poisonous from the effects of the explosion. The surgeon has no explanation for this but has observed that men who have eaten them suffer 'much colic and uncomfortable heat of skin'. The diving operations carried on every slack water 'making four tides at ebb and flow a day'. The weather did not affect operations unless there was a very heavy sea.

Folios 9-13: Discussion of the effects of exposure to sea water on the different materials found in the wreck of the Royal George; including various types of wood, metal and fabrics, and hair, teeth and bones. Woods discussed include Norway fir, cedar, mahogany, elm, ash, box, lignum vitae, satin wood, oak and fine grained fir. The effects of the contact of wood with different metals is also discussed, copper and brass having less effect than iron. This proves 'that the salts of some metals may have a different detrimental action on wood' and suggests that salts of some metals may preserve wood, as proved by the reports on use of bichloride of mercury and Sir William Burnett's experiments with zinc. Hemp, cotton and flax all suffered equally and lost their texture with the exception of well tarred hemp. Experiments carried out at Portsmouth Dockyard found some inner strands of cable to be nearly as strong as when new. Silk, leather and wool were found to 'possess durability to an astonishing degree'. Several articles of clothing were found to be almost uninjured, particularly some pieces of bobbin lace, silk handkerchiefs and satin breeches. Woollen goods and shoe leather were less resilient, although better tanned leather, such as sword scabbards and book bindings, was less affected. The surgeon 'can only account for the shoes having suffered most by the decomposition of the poor fellows who wore them having induced a more rapid decay' 'Bones, horn, hair, teeth, ivory all possess the quality of great durability'. From those the surgeon has collected he is able to say they preserve better in the sea than in the earth and that hair, teeth and ivory preserve slightly better than bones and horn. Glass is found to have suffered more than the surgeon would have expected, becoming more brittle. He suggests that the sea water may have dissolved the 'potassa' in it, leaving a higher percentage of silica. All the glass recovered 'was covered with a thin film which decomposes the rays of light, throwing off nearly all the colours of the prism'. Of the metals, gold, copper and brass were least affected, then 'Britannia metal', pewter and lead, though the lead was corroded, silver and iron suffered most. Cast iron and steel increased in bulk by 'a plentiful deposit of some of its salts and a disposition to form plumbago', while at the same time losing weight.

Folios 13-15: A discussion of the combustion of plumbago on exposure to the atmosphere after long immersion in sea water. The spontaneous heating of plumbago on exposure to the atmosphere is disputed, although it has been noticed by Berzelius, Dr McCulloch, Dr Thompson and others. The process requires 100 years of submersion and was not observed in any of the guns from the Royal George but was observed on some guns that were raised from the Edgar, which sank in 1712 [1711]. The surgeon commented on this in a nosological return at the end of August. Iron from the Edgar was seen by the surgeon to heat to 210 and to 250 degrees Fahrenheit, but he is not prepared to say it was hot enough to ignite other substances. He tells the story of a gun recovered from Sir Cloudesley Shovell's fleet, wrecked off the Isles of Scilly, and set up on St Mary's which caught fire from an accidental blow setting off the powder in it. He disputes the story however, as no similar results could be produced by striking the guns from the Edgar, heating only occurred after a few minutes exposure to the atmosphere. Analysis of the plumbago showed it to be 'an impure carburet of iron, unchemically united with the protoxide, and the affinity which the latter has for oxygen is the cause of its giving out heat, the result is probably a carbonate of the peroxide mixed with other salts'. The surgeon discusses the possible series of reactions which might produce plumbago and offers the theory that the 'property of spontaneous combustion retrogrades and possibly after a time altogether ceases' as explaining the combustion of the gun at St Mary's but not of those from the Edgar, and the discrepancies in the works of different writers on the subject. Steel is said to have a similar disposition to form plumbago but none of the specimens seen by the surgeon gave out heat.

Folios 15-16: A discussion of the power of water to transmit a shock to a great distance. The surgeon is not aware that this property has been illustrated so well as by the effects of explosions made at various distances from divers at work on the Royal George. The first example of this was 'an explosion of 10lbs of powder on the Mary Rose at a distance of three quarters of a mile from the Royal George' which knocked down two divers at work on the Royal George and frightened them a good deal. A charge of 240lbs on the Boyne at a distance of at least two and a half miles nearly stunned them, 'they felt as if struck about the heads with a crowbar', they were thrown down and shaken by it. They were not so frightened, however, since 'they were aware that the explosion would take place and consequently more prepared for it by the effects of the former one on the Mary Rose'. The explosion of larger charges, such as the 2400lb charges sometimes used on the Royal George, could be fatal even at 5 or 6 miles, but even smaller charges could endanger life by 'derangement of the diver's dress'. The effects of the 2400lb charges were felt much less on the Success, barely a cable length away, than they were on the shore.

Folios 16-17: Discussion of the health of the divers employed on the Royal George and some of the symptoms they suffered. Their health was affected by the frequent and sometimes long immersion they experienced. They often daily descended four, five or six times, remaining at the bottom for one or two hours and sometimes much longer, Diver Hall having been four and three quarter hours under water. It seems more fatiguing to be in deep water than shoal. The lungs were not affected as much as might be expected, none of the divers had pulmonic attacks, sometimes there was spitting of blood but this was from the throat, fauces or nares. Severe attacks of acute rheumatism were common, sometimes of a chronic nature, arising from diving whilst the circulation is quicker than natural, the dress admitting water or longer immersion than usual with greater exertion. The surgeon discusses the effect of fear or lack of confidence in new equipment. The symptoms whilst below are more distressing and they may suffer 'a sense of oppression, almost insufferable heat and profuse perspiration' and giddiness, the effect which is most dreaded because of the danger of falling. The most unpleasant effect is pain in the ear drum, produced by the irregular action of the air pump. In addition 'a ringing in the ear sometimes becomes very disagreeable, dimness of vision, acute pain over the forehead and eyeballs, the nose stuffed up..., pain at the epigastrium, bleeding from the throat, nose and ears, cold clammy sweats and confused ideas complete the catalogue'.