Fish Guano.

Otago Witness, Issue 2556, 11 March 1903, Page 9

Fish Guano.

TO THE EDITOE.

Sir,— ln your Notes and Queries of the last issue, I notice an answer to someone in Stewart Island requiring information on the conversion of fish and fish offal into fish- guano. It seems to me that .the reply fromi a correspondent is scarcely all that is necessary, or, indeed, quite correct in th«f process of manufacture. The discovery of this process is dv to the Jate Edwin Pettitt, C.E., of 145 Afton Grove, Southgate road, London, who was a partner of the writer's in one of hit early patents, and being his guest when in London, became an interested party in this patent to the extent of one-twelftb of the whole affah, and of course took a deeper interest in the matter than bare outsiders. I will now repeat that which is a matter of history. Whenthe Corn Laws Bill was passed, farmers were in a measure thrown upon their own resources to improve their land with the best fertilisers. Gibbs, Bright, and Co., Liverpool, held a mon6poly of the guano deposits in Peru t xhe manure being sold at 12 guineas per ton. Investigations showed that there were thousands of tons of guano sold more than were imported into the country, which was a clear proof of tlte amount of adulteration going on. The Royal Agricultural Society offered a reward of a thousand guineas and a gold medal to anyone who wpuld discover a manure equal to Peruvian guano in, fertilising properties, and which could be sold at a less cost. At this time (1852) an exciting diplomatic correspondence was. passing between the British Government and the Governments of America as to the right of possession of the guano deposits on the Isle of Labuan, and the public mind was in consequence alert to anything bearing on this very important question. Now to the discovery: Mrs Pettitt had pickled some sprats in vinegar, and showed them to Mr Pettitt in a pulp. Here, then, was the solution of the problem, which flashed over his mind at once. The guano birds live on fish, the excreta of the birds forms our guano; vinegar, a weak acid, dissolves a email fish, a Btronger acid will dissolve a larger one ; all there is to do is to chemically decompose the fish in .a similar mannei to that which is effected in the stomach of the birds, artificially dry the residuum, and the result is guano. A larg quantity was locally made, and samples sent to Professor Way. Others, again, ■were sent to Prince Albert* model farm, to Mr Mechie, of Tiptree Hall; Mr Caird, of Baldoon, the commissioner. The analysis and the practical tests were such as to induce Mr j Pettitt to secure the gold medal and the 1000 guineas, enabled as- he was to produce this manure at one-third the cost of the Peruvian article. Those who wish to avail themaelvcs of the process mentioned ought to collect all fish offal — the offal being the most valuable, containing, as it does, a considerable quantity of nitrogen; collect also any fish or the fish refuse ; put them, through what is .known as a "digester," though a pulveriser would be a better name. The bones are crushed up to a pulp, with the fishy parts, in this machine; then sulphuric acid or muriatic acid is sprinkled through the mass. When putrefaction begins to show, have some dry earth ready. This earth absorbs the ammonia. Keep adding until the mass is fairly like dry paste. There is then left nitrogen from the offal, phosphates from the bones, and ammonia in the dry earth. A friend in Port Chalmers tried this, but omitted the. dry earth, the result being a toft

* pasted with "tlie ammonia" escaping," wharih destroyed the coatings of paint on our railway '- waggons, caused the loss of a valuable fertiliu- ■'■ ing agent, and a loss to the- manufacturer ; and, what wa& still worse, ,the manure in such. { a state could not be used in the, drills. j I have now given all the? information thai I L know, and hope it may. be*of service to-sonSßbne' , who would render a bye-product of commercial! value. — I am, etc., J. Fobstth. Caversham,, March 9, ;-;"*..{ „,,,"