be seen. Considerable ice came down, however. In about 20 minutes the 

 berg could be heard calving repeatedly. Much ice was brought down by the 

 exploNiun. Three growlers, the result of this calving, and much loose ice, were 

 seen later when the fog cleared. 



May 21, a. m.: The berg being appreciably smaller and presenting in one 

 place a sheer wall without overhang about 15 feet high, succeeded in casting 

 a grapnel in a small crevass in the toj) of this wall, after several attempts. Sus- 

 pended mine about 10 feet below water and fired. Much loose ice came down, 

 as well as several growlers. The water line of the berg was considerably changed. 



May 21, p. m.: On this occa.sion a grapnel was cast upon an overhanging 

 ledge covered with lyroken ice and about 10 feet above the water. The mine 

 was lowered about 20 feet below the surface of the sea and fired, doing the greatest 

 damage as yet observed to the berg. 



May 24, a. m.: On this occasion, profiting by previous experience, exceptionally 

 smooth sea, and the further reduced size of the berg, a very careful examination 

 was made, the under-water form and approximate center of gravity of the berg 

 were roughly determined, and from this the best location for the mine. This 

 was under a smooth wall of ice, slightly overhanging and from 15 to 35 feet high. 

 Grapnels could not be made to catch in the ice. A 14-pound lead was hove over 

 the wall, but it did not offer sufficient resistance to counterbalance the weight 

 of the mine. A loop was gotten around the most prominent knob of ice available, 

 but slipi>ed off. Then proceeded to other side of berg, and with shoulder gun 

 shot a line across, so that the projectile fell where it was desired to plant the 

 mine. Two oars and a sounding lead were now attached to the shot line and the 

 boat returned and picked up the projectile, pulling in on the shot line until the 

 oars held on the other side of the wall. The mine was attached to the shot line 

 so that it would hang about 1^0 feet under water and then exploded. Much ice 

 came off the berg, ivhich rose considerably out of water on the side facing the 

 boat and then broke squarely in two where the mine had been placed. 



On May 20 berg 17 was observed well within the GuK Stream. In- 

 stead of floating in water of 38°. it was now nearly immersed in 

 water warmer than 60°. Under such circumstances various stresses 

 and strains arc set up which react in an accelerated calving and 

 general disintegration. It is not long before a bulky berg becomes 

 furrowed, pinacled, and quite irregular in shape. The weather to 

 the southward of the 41st parallel within the bounds of the Gulf 

 Stream permits work with small boat with gentle breezes and a smooth 

 sea. Such a condition in respect to berg 17, on May 20, offered 

 excellent opportunities to test the efficacy of explosive demolition 

 of a menacing iceberg in the steamship lanes. The result of this work 

 from May 20 to May 24, in which four explosive charges were fired, 

 has been described. It is believed that the employment of explosives 

 to hasten the disintegration of bergs is restricted in its practical 

 application to those bergs which are observed drifting south of the 

 41st parallel. Bergs in this location are a distinct danger not only 

 to cargo steamers, but also to the passenger liners plying between 

 Europe and the United States. True, the drift of berg 17 was 

 extraordinary. Records show that on the average one iceberg 

 drifts south of the 40th parallel every four and one-half years, but 



