SAN FRANCISCO BAY.-See Proceedings of American Wood-Preservers' Association, 1920.

Puget Sound:

Date

Temperature Readings °F Surface Temperature Readings °F Mud Line

NEW YORK HARBOR: The following temperatures were taken by the Metropolitan Sewerage Commission of New York in 1912 and 1913 at Pier A, Hudson River mid-stream:

The following temperatures were taken by the New York Aquarium at the Battery, New York City, at 3:00 p. m. daily in 1920:

The following temperatures were taken by the U. S. Weather Bureau at Pier 13, North River in 1889:

Extensive observations of this character are now being planned at various points in the United States. In connection with the figures just given it is pointed out that while temperature and salinity determinations made in regions where marine borers are active are of considerable value, it will nevertheless be necessary to have observations of this character made at such points where the direct biological investigations are being conducted. Definite and accurate knowledge of the environmental conditions as indicated by salinity and temperature when considered in connection with an exact knowledge of the life history of any one particular species will be one of the best methods for determining whether one or the other species of marine borers may be expected at any particular locality. Investigations are in progress in various laboratories dealing with the breeding and food habits of various species of marine organisms concerning which comparatively little is known at the present time. European observations as to temperature and salinity have been more extensive. As a comparison some recent determinations made by the joint Danish, Swedish and Norwegian Committee in the Baltic and North Seas may be of interest. (See paper on Teredo and Limnoria.)

One of the most important phases of the work naturally deals with protective measures. In a general way two general plans have been followed (see in this connection 1920 report of the Committee of the British Institution of Civil Engineers), one to use timbers naturally immune to marine borers and the other to protect wood piles either by impregnation or by other means against the borer attack. So far your Committee has been able to find very few resistant types of timber that have ever been used in North American waters. Through the courtesy of Mr. R. A. Bainbridge, of the Esquimault and Nanaimo Railway, Victoria, B. C., your Committee was enabled to make an examination of an interesting test of Austrian turpentine piles. (Syncarpia laurifolia.) These piles have for years been used in Australia and Asiatic waters and have proven more immune than most other woods to the attacks of marine organisms. At the request of your Committee Mr. Bainbridge kindly prepared a brief statement as to his experience with these piles as follows:

"Replying to your letter on Sept. 8th, asking for further information regarding our experience with timber piles in Victoria Harbor and adjacent waters around Vancouver Island:

"I might say that our experience with Australian turpentine piles during the last fourteen years is very satisfactory, and we find that they resist attacks of teredo absolutely. The limnoria, or water flea as we call it, does affect them to a slight degree, they eat piles from the outside, cating them off to a pencil point. I find that they have made a slight impression on the Australian piles which have now been in service for over fourteen years, but they have made very little headway as yet, the reduction in the diameter of the pile being barely perceptible. Victoria Harbor is not much affected by teredo on account of the large amount of fresh water flowing into the harbor. On the east coast of the island at Ladysmith, Nanaimo, and Nanoose, and at Port Alberni on the west coast, the teredo is very much worse and from recent experience it appears to be more destructive in the last two years than formerly. At all the above points we have Douglas fir creosoted piles in use, and so far we have found they resist the teredo, but they have only been in place for seven years, which is not a sufficient length of time to be able to state how long they will last, but as the tops of these piles will rot out in twelve to fifteen years, it would appear that we will get that much service out of them.

"But the Australian turpentine piles will last indefinitely, as they do not rot, and appear likely to last for one hundred years. The Australian pile referred to is locally called 'turpentine tree,' from the eleo resin produced by the tree. The botanical name is 'Syncarpia laurifolia, Ten.'

"Referring to the assertion that the teredo appears to be getting worse in the last few years, I may mention that at Ladysmith, new timbers were put in a railway trestle approach two years ago, frame bents of Douglas fir on sills completely dry at fairly low tides. These timbers, and the sills especially, have been completely eaten out, being riddled by teredo, and the sills broken in two, and had to be completely renewed. Such extensive damage in so short a time is unprecedented, especially when the timber is bare at low tide. At Nanoose Bay there are some boom sticks fending vessels off dolphins, floating on top of the water, which are partly affected by teredo. This also is an unusual occurrence.

"In conclusion, I may state that in my experience the Australian turpentine piles are the best and cheapest article to use on the Pacific Coast, if they can be procured, but of recent years we have found it almost impossible to get them on account of scarcity of tonnage.

"This obtacle is, of course, now removed, but I am not sure but that the Australian Government has placed an embargo on the export of these piles. There is one other fact I may mention which might be

useful, and that is the use of Douglas fir piles got off rocky land and highly resinous, especially in the butt. We drive these piles butt end down so that the portion of the pile above the mud is more resinous than the top portion, and successfully resists the attacks of teredos for a much longer time."

In view of the fact that turpentine piles are usually recommended for use with the bark on, it is interesting to note that Mr. Brainbridge on the subject referred to advices that these particular piles which he used had the bark on, but most of the bark stripped off before the piles were actually driven. An examination made by your Committee during the past summer of the turpentine piles driven in 1911 at Victoria shows them to be practically free from borer attack, whereas Pacific Coast timbers were eaten off in less than a year.

Through the courtesy of Mr. H. N. Rodenbaugh, Chief Engineer of the Florida East Coast Railway, the Committee is in receipt of the following report on the use of Jucaro piling on the Florida East Coast Rail

way:

"Jucaro timber is found in the Eastern end of Cuba, there being two kinds used for piling, namely negro' (black) and 'blanco' (white). Of the two the negro is the better wood. The wood resembles the shell bark hickory in appearance with a bark much like the burr-oak. The heart wood is a dark brown and the sap a light cream color.

The sap will not withstand the action of worms, but the heart wood has been found very resistant against the action of both the Teredo and Limnoria, as will be seen from the accompanying photographs taken of a section from a fender pile in Key West Harbor after seven years' service. It will also be noted that though the sap is honeycombed to a great extent it does not slough off as is the case with pine piling.

To secure the best results from these piling, it is quite necessary to secure green piles and drive them with as little delay as possible, as the timber decays very rapidly when stacked. Above water the sap is quite prone to rot but below water rotting occurs so slowly that it is scarcely perceptible. So far as can be ascertained the heart is very resistant to rot, as is the case with numbers of other tropical woods. However, if the top of the piling is cut off square with a saw and left unbanded, the sun and weather will split the pile in many and long rifts. To overcome this the top should be rounded off and wrapped with several turns of heavy galvanized wire, securely fastened about six inches from the upper end.

These piling drive with considerable spring and are not as easy to drive as green pine or creosoted piles but will withstand considerable pounding. It has been estimated that in bearing qualities it ranks between the Dade County pine and oak. No figures on this feature were obtainable.

These piles are very expensive and the price per foot varies considerably with the length and heart. The high cost is due to poor transporta

tion facilities as they are found in a hilly country quite distant from either railroad or water transportation and have to be handled for a number of miles with oxen; furthermore, there are only certain seasons when they can be gotten out on account of weather conditions.

The latest prices obtainable were on 5500 lineal feet of 50 feet piles purchased by this Company in 1918 which cost, including the freight to Key West, $1.84 per foot.

In view of the fact that creosoted piles have been the chief reliance against marine borers the finding of some old piers built with creosoted piling in San Francisco Bay at the time of the recent outbreak was of unusual interest. Members of your Committee made a preliminary examination at the time that the piles from the Southern Pacific piers referred to were pulled. Note in this connection, preliminary report by F. D. Mattos in 1920 Proceedings of the American Wood-Preservers' Association, Page 148. The oldest piles in these piers were creosoted in 1889, and from then on up to 1897 only creosoted piles were used in the construction of these piers. Due to harbor line changes all piles were pulled in 1919 when it was found that a high percentage of these old piles was still in sound condition, fit for redriving, specifically from Dock C driven in 1897, 63.67 per cent.; Dock D driven in 1889, 76.06 per cent.; Dock E driven in 1901, 76.46 per cent.; or taking all of the piles inspected to the number of 4,098, 3,062 or 74.72 per cent., were sound enough so that they could be used over again. (For details see American Wood-Preservers' Proceedings of 1920, Page 148.) This remarkable record, unequaled by any marine structure in North American waters, could have been due either to the absence of the marine organisms or to effective protection. In order to determine as quickly as possible whether the conditions surrounding these piles were responsible for their long life, arrangements were made to transplant some of these old piles to other waters. Through the courtesy of the Southern Pacific Railway Company, the Santa Fe, the Northwestern Pacific, the Northern Pacific and the Louisville & Nashville Railroads a number were transplanted as per the following detailed statement:

A. T. & S. F. Ry.

The following Douglas fir piles were driven at San Diego, Cal., in Santa Wharf No. 63, in 1919: