INVESTIGATIONS RELATIVE TO ILLUMINATING MATERIALS. 499 



oil as a burner. I fully believe that our rape-seed oil of this year is as 

 good as any that was ever made in Europe, and 1 kno^Y it is far better 

 than any we have ever before made. I am satisfied now tliat, for self- 

 heating lamps, there is no oil that will bear comparison with lard, but 1 

 am equally satisfied that no colza oil will yield a better result than ours, 

 under exactly the same tests. We have but one more experiment to 

 make with colza ; it is its extraction by chemical disi)lacement. If this 

 fails, we shall abandon .the whole business. 



If all things are put together, I think the following statement will 

 be allowed, to wit : Our colza oil is equal to any foreign colza. It is better 

 than any we have heretofore made. It is better than sperm or any other 

 burner, excepting only lard-oil. Our failure then is owing to the supe- 

 rior excellence of lard-oil, which, under the persistent investigation of 

 the board, has been shown to be the best and cheapest safe illuminator 

 available. 



The board are entitled to great credit in producing this result. It 

 will be remembered that but a few years since lard-oil was pronounced 

 unsuitable for light-house purposes, but the perseverence of the board 

 has brought out the fact that it is much the best and cheapest oil, and 

 that the expenses of lighting the coast and harbors have been thereby 

 greatly reduced. Surely the country at large should acknowledge this, 

 and give due credit to the board. We have endeavored to do with colza 

 what the board have effected with lard-oil, and we have been unsuccess- 

 ful both for ourselves and the light-house interest. The undertaking 

 has been no source of profit to us, and had the capital and time that 

 have been devoted to colza been used in our other branch of manufac- 

 ture (linseed oil), it would at least have reimbursed us with a fair re- 

 munerative return. As regards the oil we have offered, we have hoped 

 the board would take it. I do not think we can improve upon the qual- 

 ity, and it is the last we shall venture to offer to the acceptance of the 

 board, for we shall henceforth abandon the manufacture, except for local 

 wants. 



We are grateful to each member of the board for the interest they 

 have always shown in our undertaking, and for their uniform kindness 

 and courtesy. Accept, my dear commodore, for yourself and your asso- 

 ciates in the board, ray warmest thanks for your many kind expressions 

 of interest, and beUeve me, truly and gratefully, yours, 



0. S. Hamilton. 



Com. A. A. Harwood, TJ. 8. N., 



Secretary Light-House Board, Wasliington, D. C. 



From the date of the introduction of lard-oil in 18G5, '60, and '07, until 

 the end of 1873, when the attention of the board was again directed to 

 the study of mineral oil, continual improvements were made in the pro- 

 cesses of its preservation and inspection, and also in the lamps and 

 other appliances for its employment, and nothing fui'ther as a light-house 



