238 Thirty-Third Annual Meeting 
and white lead proved to be the most durable, and, to anticipate 
somewhat in the account, lasted for about two years. In the case 
of this material, both wire and covering were very light and sub- 
sequent experience has shown that a heavier wire is much more 
durable. Asbestos cord was found to be practically indestructi- 
ble chemically, but when wet the fibres become so slippery and 
loosely laid that the tensile strength is greatly reduced. This 
difficulty was overcome by treating the asbestos with rubber solu- 
tions, white lead, a mixture of paraffien and asphaltum, and 
other waterproofing and cementing substances. These treat- 
ments very greatly increase the strength of the cord, but the 
‘rubber treatment is somewhat expensive and the asphaltum for 
some reason causes undue abrasion of the sponge. Lead wire 
possesses the important quality of permitting a true organic at- 
tachment of the sponge which thereby clings to its support quite 
independently of artificial attachments, but its tensile strength 
is so low that it is unable to support its own weight to say noth- 
ing of the weight of the sponges and the pressures oer by 
waves and currents. 
The terra cotta and cement blocks used on the bottom were 
found unsatisfactory for a number of reasons. They were cap- 
sized by the waves in many cases and the cuttings buried in the 
mud and even when they remained upright silt and vegetable 
matter in a great many cases destroyed or injured the cutting. 
The results enumerated, the very evident advantages of raising 
the sponges above the bottom, and the mechanical advantages of 
planting and raising the sponges on wires all operated to dis- 
courage further experiment on these lines. 
During the winter of 1902-03 certain changes, founded upon 
the experiences of the previous winter, were made in the charac- 
ter of the materials used through the general method of making 
and fixing the cuttings was the same. 'To get the virtues of lead 
its chemically inert and innoicuous qualities, and at the same 
time to eliminate its vice of tensile weakness, the device was hit 
upon of using ordinary tarred marline encased in lead of a thick- 
ness of about one thirty-second of an inch. The marline core 
furnished the necessary strength, and the lead casing, besides 
protecting the cordage to some extent from decay, furnished the 
basis for an organic attachment of the sponges, a desideratum of 

