On the Use of the Diving Helmet in 

 Submarine Biological Work* 



By K. \V. (i r I) (i i: K" 



Professor of RioloK.v. Stntc Normal ColU'ge, tircoiishoro, Xortli Ciirolinn 



IN a luiiiihtM- of tho liulh till of I Ik .V« n- 

 York Ziiokuiical Soviet ti f«tr 191ti, l>i-. 

 Alfred G. Mayer i referred incidentally to 

 the use of a diving helmet for work in siil)- 

 niarine biology at the Tortugas, Floriila, 

 Marine Biological Laboratory of the Carne- 

 gie Institution of Washington, and gave a 

 figure of such an ajiparatus in actual use. 

 In accordance with Dr. Mayer's customary 

 liberality in providing everything available 

 for furthering the work at Tortugas, the use 

 of such a hood there was inaugurated in the 

 season of 1915. At that time this helmet 

 was a new thing, and its utilization for the 

 study and collection of marine organisms in 

 their natural habitat was thought to be its 

 first use for such a purpose in the liistory 

 of science. However, such is not the case. 



At Tortugas, during the season of 1915, 

 Prof. W. H. Longley and Dr. Lewis R. C'ary 

 did considerable experimental work with this 

 diving helmet. During the summers of 1916 

 and 1917 the helmet was in very frequent 

 use, both these men becoming quite skilled 

 in descending to moderate depths and in 

 studying the fauna and flora there. By its 

 use Professor Longley was enabled to go 

 ilown on to the coral reef off Loggerhead 

 Key and there, in Dr. Mayer's words, "to 

 become a fish among the fishes," which he 

 studied literally at arm's length. Thus 

 equipped and thus located, he has made ob- 

 servations of the habits of reef fishes as 

 valuable as they are interesting. Further- 

 more, wearing this helmet and using a cam- 

 era contained in a specially devised water- 

 tight metallic Vjox, Professor Longley has 

 been able to take some remarkable sub- 

 marine photographs of the fishes in the 

 rocky recesses of the reef, their home. Es- 

 pecially valuable are these photograjjhs in 

 the study of. the changeable color phases of 

 the fishes when under the influence of vari- 

 ous emotions, or when changing from one 



' Mayor. Alfred G.. Longloy's and Rpighard's 

 Studies of the Reef Fishes of the Tortugas. Florida. 

 Bulletin Xew York Zoiiloijical Soriiti/, 1916, vol. 

 19. pp. 1.335-1336. 1 fig. 



* Indebtedness is acknowledged to Mr. W. F. Mil 

 Florida, for the use of the illustratioiiK in this artii-le. 



colored snbstratiiiM to another, or when vary- 

 ing with the amount of light received. - 



The diving helmet'' is really an appara- 

 tus as sinii)le as it is efl'ective for tise at 

 moderate dejiths. It consists of a barnl- 

 shaped brass hood with a conical top having 

 a handhold or grij) for putting it on or lift- 

 ing it ofT the head of the diver. In front, 

 <'orresponding in position with the face of 

 tiie diver, is a ]>late glass window through 

 which the wearer makes his observations. At 

 the base of the hood are metal flaps de- 

 scending a short distance over the lireast and 

 back of the wearer Init cut away in th<' 

 region of the shoulders to let the apparatus 

 fit snugly and securely around the neck and 

 on the shoulders. To the back flap, and if 

 necessary to the front one also, may be at- 

 tached masses of lead to overcome the buoy- 

 ancy of the diver and to hold him firmly on 

 the bottom. Fastened to the hood is a rub- 

 ber hose extending to the attending boat at 

 the surface where it is connected with a 

 double-cylindered hand pump worked by a 

 long lever so attached as to compress the air 

 in each cylinder alternately. The respired 

 air, together with the excess of air driven 

 into the hood by the pump, escapes under 

 the edge of the hood in a great stream of 

 bubbles. The shallow and w^onderfully clear 

 water at Tortugas makes it possible for a 

 man sitting in the boat and using a "water 

 glass" (a bucket having a pane of glass set 

 in the bottom) when the surface of the water 

 is covered with ripples, to see easily what is 

 going on below and hence to regulate readily 

 the amount of air sent down for the use of 

 the diver. Professor Longley found that 

 about eighty pounds of "ballast" were nec- 

 essary to steady him on the bottom in water 

 from eighteen to twenty feet deep, and that 

 he could easily remain down for thirty min- 

 utes in comparative comfort. 



- Longley. W. H.. Studios upon the Biological 

 Signifiranee of Animal Coloration. Journal nf 

 Kxpfrimtnlnl /oiiloi/n. 1917, vol. 23, pp. 533-600 

 1 pi. 



^ Invented by Mr. \V. .S. Dunn of Miami. Florida. 



.r. president of the Miller Dunn Company, Miami, 

 as well as for valuable data. — K. W. G. 



i:i5 



