DOUSLIN'S LOG DAMS

Marlborough Express, Volume XII, Issue 940, 28 July 1877, Page 7

DOUSLIN'S LOG DAMS

Sir,— A letter signed <# Heriry Dodson" which appeared in the Express a fe-w days ago, deserves a little comment. The writer has evidently average ability, but mars what little argument be uses by a scarcely suppressed spite at Mr Douslin. His private feelings we have nothing to do with, and I would advise him not again to mix up the dams — his own experiment for the protection of his property at the public expense— and his ill-feeling , to Mr Douslin. It makes rather a sad jumble^ and as one of the public I refuse to judge of Mr Douslin's experiments through such spectacles. We have nothing to do with the wretched squabbles , of the great little men of the past— let us consider the experiment apart from them and even the inventor. We find through all the late freshes much less water in the Opawa than there has been during previous years, and a trip to Rock Ferry will show the reason of this. There is no doubt nor room for cavil that there the river has attacked the North side ; and if it were not for the wretched parsimony of the Board of Conservators in not lengthening the dam, the river would be driven further north and a flood in the Opawa rendered an impossibility. I have lately visited the dam at Leary's but not looking at it through such spectacles as Mr Dodson's I 'considered it such a success, that I considered any further comment unnecessary. If Mr Douslin had surveyed the river for the purpose of finding the most unfavorable spot to try his experiment at, he could not be so well suited anywhere, as at the very spot he was forced to erect the dam. The river falls behind it 8 or 9 feet in a few hundred yards. The dam had also to be constructed to suit two streams instead of one, Jackson's Creek and the Opawa. During flood time the angle formed by the combined streams is the proper one, and the dam acts well, but when there is no water in Jacksons, the Opawa strikes the dams too directly, and may, unless the rear of the dams is closed up, silt the new chan- [ nel. The fcure for this is simple. Check jor prevent by slabs of logs the still water behind the dams from gaining motion by rapidly descending the river and force |,it through the new channel. During flood time, Avhen the combined streams are operating, there is no necessity for this ; but the fall is so close to the rear of the dams that the shingle is partially washed away as soon as Jackson's Creek is closed from want of water. So far then, in my opinion, as the logs are concerned, and taking Eock-ferry into consideration along with Leary's, the dams must be pronounced a success. The Board of Conservators can now see for themselves how the dams at Leary's can be rendered perfect. The statement that floating logs make holes under them is true. They form eddies by checking the current which proves the principle right. All that is required is to place them at the proper angle, and put in as many as will bear a proper resist- . ing surface to the water. Ido not wish it to be understood that I condemn anything Mr Dodson has done to his own property. On the contrary, I believe he has done the work well and may|turn out a heaven-born Civil Engineer. And even had he partially failed, the experiment was worth trying. There is much to be learned yet on the subject of River Conservation, but persons feeling the divine afflatus ■within, that tells them they are fitted for higher things than their ordinary life should try to suppress their natural jealousy of others. The public of course may gain between, the rivalry of Mr Douslin's experience and professional knowledge and Mr Dodson's intuitive ability and latent genius, but I hope we will be spared all petty spite and personalities. Engineer. [As Mr Dodson signed his letter, ""Engineer" ought to have done the same, especially when introducing personalities. In future letters of the kind must be signed to obtain insertion. Ed. M. R]