October 21, 1920] 



NATURE 



r 



The Durability of Maritime Structures. 



Committee of the Institution of Civil Engineers. 



» appointed to Investigate the Deterioration of 

 Structures of Timber, Metal, and Concrete Ex- 

 posed to the Action of Sea-water. First Report 

 of the Committee. Edited by P. M. Crosthwaite 

 and (jilbert R. Redgrave. Pp. 301+xxxiii 

 plates. (London : The Institution of Civil 

 Engineers; H.M.S.O., 1920.) Price 30^. net. 

 HE deterioration of buildings from ordinary 

 physical causes has always been one of the 

 most important considerations before the engineer 

 and the architect, and in preparing their designs 

 they have been under the necessity of adopting 

 precautions and protective measures of various 

 kliuK. But the destructive influences which have 

 to be counteracted under ordinary atmospheric 

 conditions become tenfold more active and per- 

 nicious in a marine environment. The acidity and 

 salinity of sea-water ; the fluctuations of tidal 

 level; the alternations of wetness and dryness in 

 rapid and rhythmic sequence ; the impact of waves, 

 producing vibration ; the penetration of wind- 

 driven spray and the insidious attacks of marine 

 organisms — all these result in an intensification 

 t of the ordinary process of decay. Although the 

 f phenomena are well known and their effects only 

 ; too patent, yet until recently definite and trust- 

 worthy evidence as to the rate and extent of 

 <leterioration was not readily obtainable. Con- 

 ditions varied greatly with the locality. Counter- 

 acting agencies, some obscure in origin, necessi- 

 tated modifications in general conclusions. 

 Records were but indifferently kept. For these 

 and other important reasons, the Institution of 

 Civil Engineers felt it imperative, in a matter of 

 such vital concern, to set to work to collect such 

 data as were available, and to institute investiga- 

 tions and experiments on a scientific basis. It 

 accordingly appointed a committee of thirteen 

 engineers of high standing and reputation, who 

 co-opted four additional members, and these 

 gentlemen have just issued their first report. 

 Some forty ports in various parts of the world 

 were selected as the field of inquiry, and memo- 

 randa furnished by the respective local engineers, 

 or abstracts therefrom, as to the condition of 

 typical existing structures, are incorporated in the 

 report. 



The volume commences with an abstract from 

 the Proceedings of the Institution of Civil Engin- 

 eers of information contained in various papers 

 relating to the subject. This has been prepared 

 by Mr. G. R. Redgrave, who collates the data 

 under the heads of timber, concrete, iron and 

 steel. Mr. H. W. FitzSimons, in conjunction 

 NO. 2660, VOL. 106] 



with Mr. F. T. Brooks, contributes a useful article 

 on the value of timber as a material for marine 

 structures, with botanical observations and notes. 

 Next is a short monograph on marine boring 

 animals, prepared by Dr. Caiman, of the depart- 

 ment of zoology, British Museum. This classifies 

 the information at present available relative to 

 the Teredo and its allies, their habits and dis- 

 tribution. Dr. Friend follows with a paper on 

 the corrosion of iron and steel, and the remainder 

 of the book is taken up with the special reports 

 (fifty-two in all) from engineers in different locali- 

 ties. There are two summaries at the end of 

 the volume; the first, prepared by Mr. M. F. G. 

 Wilson, is a synopsis of the local reports in 

 regard to special features, and the second is a 

 general report embodying the findings of the com- 

 mittee on the investigations as a whole. 



The volume is, undoubtedly, a most useful col- 

 lection of data and results, collected at consider- 

 able trouble, and for the first time collated in 

 order and degree. At the same time, the diversity 

 of testimony is so evident, and the lacunw are 

 so considerable, that the preliminary impression 

 created is one of greater perplexity than before. 

 Even Mr. Wilson has found it difficult in several 

 cases to reconcile conflicting statements, nor can 

 the local engineers always explain certain incon- 

 sistencies in the records of their experience. This 

 is, perhaps, most particularly noticeable in regard 

 to the depredations of marine organisms. Thus, 

 of the activity of Limnoria on creosotcd pitchpine, 

 it is recorded that of two i4-in. square piles, 

 located only 40 ft. apart in Holyhead Harbour, 

 within a period of nine years one was reduced to 

 9 in. in diameter, while the other showed no sign 

 of attack. In the estuary of the Mersey, adjacent 

 to the open sea, the Teredo has been found only 

 "in a few cases," and causes no trouble; at Bom- 

 bay its ravages have been so devastating as to 

 lead to the abandonment of timber for permanent 

 sea works. Thus at the present stage it is only 

 possible to form conclusions of a somewhat broad 

 and tentative character, which will be the subject 

 of closer investigation and later review. 



The idiosyncrasies of timber-destroying organ- 

 isms are particularlv stimulative of inquiry, and 

 not the least interesting feature of the report is 

 Dr. Caiman's study of their anatomical stnu iiit< , 

 development, and method of attack. The organ- 

 isms include the ship-worm (Teredo), the gribble 

 (Limnoria), .SphaTonia, and Chelura. The first is 

 a mollusc, the others arc crustaceans. The family 

 Teredinidie is a comprehensive one, and includes 

 not only the typical genus Teredo, but also the 

 allied genera, .\ylolrya and Nausitora. Species 

 of the same genus, moreover, differ widely in 



