[from a typescript in the Central Archives]
My Dear Sir
I have not the slightest doubt that I could already make use of the Calotype apparatus, and if I was remaining in England should delight in watching its progress – and I look forward to using it on my return – but considering the great imperfection in the manufacture of paper suited to the purpose, the nicety required in using the chemicals, and the extreme cleanliness and exclusion of light in the process, I fear the science is not yet ripe enough for the use of the rough traveller, I am called upon to say if it is requisite for the Expedition? – and considering the increase of care and trouble given to the party, – the cost of the fitting out, – as well as thinking the subjects not altogether applicable to show the best power of the instrument, I cannot recommend its adoption unless an experienced person is sent to attend solely to the subject.
I am quite ashamed at the trouble we have given you, but am sure that our whole party are sensible of the extreme beauty and promising use in the invention.