July 7, 1922] 



SCIENCE 



19 



ber 20, 1921, and January 1, 1922. Their 

 weight varied from 250 to 300 pounds. 



With this information I called at the office 

 of the Atlantic Coast Fisheries Company, 

 owners, at Fulton Market, where Mr. J. M. 

 Matthews, in charge of the office, after inter- 

 viewing Captain Emil Rasmusen of the 

 schooner Ruth M. Martin, made the following 

 statement : 



While fishing for tileflsh 120 miles E. S. E. 

 of Ambrose Channel lightship, a swordfish was 

 found on the trawl line when hauled to the 

 surface. The fish was entangled in the trawl 

 apparently in an effort to obtain some of the 

 tilefish that had been hooked. The tileflsh near 

 where the swordfish was entangled were cut 

 and bruised, indicating that they had been 

 attacked. There was no indication that the 

 swordfish had been hooked or had taken any 

 bait. The trawl line was looped around the 

 sword close up to the head and wrapped around 

 the body several times. On this trip three 

 swordfish were taken on the trawls in the same 

 manner. One weighed 265 pounds and had a 

 sword about five feet in length. The other two 

 weighed 254 and 185 pounds, respectively. The 

 tilefish trawl had 320 hooks nine feet apart. 

 The fishing ground is on the edge of the Gulf 

 Stream. 



I then interviewed Captain Jack Rasmusen 

 of the schooner Benjamin W. Latham. He 

 reported having taken five swordfish on tilefish 

 trawls during the holidays, with a total weight 

 of 990 pounds, the trawls being set at depths 

 of 70 to 115 fathoms. 



The masters of all four vessels stated that 

 swordfish had never been caught in this manner 

 before so far as they knew. There were no 

 signs of swordfish at the surface when any of 

 the trawl catches were made. 



In going into the details of the matter, I was 

 interested ehiefiy in ascertaining whether the 

 swordfishes had actually gone to the bottom in 

 search of food, but there does not seem to be 

 any positive evidence on this point. The mas- 

 ters of the vessels thought that the unvxsual 

 catches on the trawl lines were fii-st felt at 

 about 25 fathoms below the surface. All the 

 swordfishes were much tangled up in the lines 

 and most of them were dead when brought up. 

 They probably attempted to raid the trawls 



while they were being lifted, and it is possible 

 that some of them did so at depths considerably 

 greater than that at which they were first 

 noticed. 



Chas. Haskins Townsend 

 The Aquakium, 

 New York, 



MEXICAN ARCHEOLOGY 



To THE Editor op Science: A somewhat 

 inaccurate account of the communication on 

 "Recent archeological discoveries in Mexico" 

 that I made to the Royal Anthropological So- 

 ciety in London on November 22, 1921, having 

 been reprinted in Science (April 7, 1922) 

 from Nature, I would be obliged if you would 

 permit me to refer those interested in the sub- 

 ject to the exact report of my text printed 

 in Man (January, 1922), to rectify the fol- 

 lowing inaccuracies : 



It was in 1909, not "in 1920" that specimens 

 of the sub-gravel type were first brought to my 

 notice. It was in the great pyramid of the 

 Sun at Teotihuacan and not in the recently un- 

 covered and reconstructed "small pyramid" 

 that Senor Gamio pierced a tunnel. It was an 

 age of two thousand years and not of "twenty 

 thousand years" that the late distinguished 

 volcanist, Dr. Temple Anderson, tentatively as- 

 signed to the lava bed at Coyoacan under which 

 a second type of clay figurines was discovered. 

 In his remarks Mr. T. A. Joyce referred to a 

 figurine acquired by the British Museum "from 

 Michoacan, Mexico," and not from "Ecuador." 

 Zelia Nuttall 



QUOTATIONS 

 THE ISOTOPES OF TIN 



The insensitivity of the photographic plate 

 in recording positive rays when compared with 

 its sensitivity to light has long been observed, 

 and has been accounted for by the fact that the 

 action of positive rays is purely a surface effect. 

 There has, therefore, always been the hope that 

 considerable improvement could be made in this 

 direction by increasing the concentration of the 

 bromide partieules on the surface of the gela- 

 tine. This hope has now been realized to some 

 extent by the u^ of a method which, I under- 

 stand, has been devised for the production of 



