T. E. Lawrence Correspondence – Page 665

place for sometime before firing, then it is better to coat the paper lid with a bitumen compound (we use Chatterton's compound, often) or with a good oil paint, before tying it on. In extreme cases (before a voyage, where prolonged delay before firing might occur) I have made two dents in the lid of the canister (for the leads) and forced the lidon again, and taped it round, exactly as it is sent out by stores. The drawback to this treatment is that too tight a lid may choke the combustion of the powder. Usually, however, the explosion of the detonator blows it off, or to one side. Warn R. D. Abn. ? that too powerful a detona-tor scatters the powder, without lighting it. I tried some fulminate caps once and failed with them completely. A sputtering, hot, powder-like ignition, such as the Pain detonators provide, is better. With my commercial caps I used rubber leads. They had only one drawback - their thickness, which made it difficult to get the lid back on again ( as inthe "voyage" w-terproofing method) or to tie the medicated paper of fabric tightly round the canister-top, in the quick-use method. Except for this, they were in every way the equal of the cotton-wound leads. I expect the experts are looking sideways at the cotton-insulation, because itdisn't a very good insulation, for usual electrical work. But they should