April 17, 1919] 



NATURE 



35 



cubic ft. The author gives a curve showing the average 

 lift per unit volume of gas at various altitudes as a 

 percentage of the lift at ground-level. .\ dominating 

 requirement in design is the provision of the longi- 

 tudinal strength necessary to withstand the longi- 

 tudinal shearing forces and bending moments, and 

 the different means adopted to meet this requirement 

 divide airships into three main types, viz. non-rigids, 

 semi-rigids, and rigids. Particulars of three non- 

 rigid airships are given in the paper, having gross 

 lifts of 4690 lb., 14,100 lb., and ii tons respectivelv ; 

 the disposable lifts when full are 1669 lb., 4655 lb.] 

 and 5 tons. For airships larger than 500,000 cubic ft! 

 the non-rigid type can be, and has been, used, but 

 its efficiency tends to compare less favourably with 

 the semi-rigid type as size is increased. The 'author 

 deals with questions of the gas pressures required 

 to enable the envelope of the non-rigid ship to main- 

 tain its form under the distorting forces due to 

 weights, and with the means for supporting the bow 

 against the external air pressure in flight. He con- 

 siders that non-rigid ships form a class of great 

 utilitv, which can be given speeds of 45 to 60 miles 

 per hour, with disposable weight percentages from 

 .33 to 45 per cent. They are particularly suitable for 

 short-distance flights and for patrol duties. Their 

 chief merits are simplicity, ease and cheapness of pro- 

 duction, and low cost of maintenance. 



In semi-rigid airships a longitudinal keel girder is 

 fitted to the underside of the envelope so as to con- 

 stitute a rigid or slightly flexible backbone. The 

 general effect of the keel is to relieve the envelope of 

 all loads which in non-rigid airships have to be met 

 bv means of a relatively high internal gas pressure. 

 As a result it is found possible to fly large semi-rigid 

 airships of more than 600,000 cubic ft. with gas pres- 

 sures at the axis little more than one-half as great as 

 those required in non-rigids of equal capacity and 

 speed. Particulars of four semi-rigid airships are 

 given in the paper, having volumes up to 1,060,000 

 cubic ft. ; the type in recent years has been developed 

 by the Italians alone. Semi-rigid airships fill the gap 

 between the largest efificient non-rigid and the smallest 

 useful rigid airship. 



In rigid airships the whole of the shearing forces 

 and bending moments are sustained entirely by a 

 rigid hull. .A. typical rigid airship has the following 

 characteristics :—' 643 ft. long by 78 ft. 9 in. extreme 

 diameter; gas-bag capacity, 1,950,000 cubic ft.; 

 maximum speed, 60 to 65 miles per hour; total lift, 

 592 tons under standard conditions ; disposable lift, 

 10 tons. The machinery weighs 8^ lb. to 9 lb. per 

 brake-horse-power. The author gives curves of 

 shearing forces and bending moments for an airship 

 of this type, both in the fully loaded and in the light 

 condition, and discusses the effects of these curves 

 on the design. 



The most striking improvement in the commercial 

 vnlue^ of airships is to be obtained by increased size. 

 An airship of 2,500.000 cubic ft. capacity, maximum 

 speed 70 miles per hour, would have a disposable lift 

 of CO per cent, of the total, i.e. about 38 tons. To 

 enable this ship to cross the Atlantic at 55 miles per 

 hour she should carry fuel and oil for 4500 miles, and 

 an analysis of the disposable weights shows that 

 there are 8^ tons available for carrying capacity for 

 passengers, lugga^^e. food, etc., which is about I'l per 

 cent, of the total lift. 



If an airship of double capacity, i.e. 5,000,000 

 cubic ft., be designed for the same length of vovage, 

 the carrying capacity works out to/ about 28 tons, which 

 is about i8^ per cent, of the total. The running costs 

 of the larger ship will be less than double those of the 

 smaller, _and hence the largei/ ship is a far better 

 commercial proposition. 



NO. 2581, VOL. IO3I 



I 



There are, of course, many problems other thai> 

 those of design to be considered in the commercial 

 airship. Thus Lord Weir directs attention to the cost 

 of accommodation, the handling facilities, and the 

 gas-producing plant. The question of mooring air- 

 ships in the open is also being investigated, and it is 

 hoped that it will shortly be possible to bring airships 

 successfully to rest in the open even in a strong wind. 



EXPERIMENTS IN PSYCHICAL 

 RESEARCH.^ 

 TN 1912 Mr. Thomas Welton Stanford, brother of 

 -*■ Leland Stanford, an"d one of the trustees of the 

 Leland Stanford Junior University of California, 

 placed at the disposal of the University the sum ot 

 10,000/., the interest on which was to be applied to 

 investigations in the field of spiritualism and psychical 

 research, and Ur. Jordan, the president of the Uni- 

 versity, asked if the department of psychology was 

 willing to assume the responsibility of applying the 

 endowment to work in this field. After some natural 

 hesitation and consultation with other universities, 

 the offer was accepted. The endowment sufficed not 

 only to refit and equip the laboratory rooms assigned 

 to the work, but also to defray the expenses of a 

 fellowship, to which Dr. Coove'r, a trained psycho- 

 logist, was appointed. The present bulky volume' con- 

 stitutes his first report. 



Part i. deals with the hypothesis of " thought trans- 

 ference" or telepathy, a subject on which much experi- 

 mental work has been done, but more, and more care- 

 fully controlled, work was urgently needed. Three 

 sets of experiments were carried out :— (i) On the 

 guessing of lotto-block numbers; (2) en the guessing 

 of playing-cards ; (3) on the " feeling of being stared 

 at." The playing-card experiments were very exten- 

 sive, and deserve a longer notice than we can give 

 them. The following was the method :— (i) The ex- 

 perimenter shuffles the pack (court cards discarded), 

 (ii) He throws a die. If the number thrown is odd 

 he holds the card in his mind, the form of content 

 being: for i, visual impression; for 2, kinaesthetic 

 irnagery (incipient pronouncing) ; for 3, combined 

 visual impression, kinaesthetic image, and auditory 

 image. (For even numbers, see below.) (iii) He 

 turns over the pack, notes the bottom card, taps once 

 to signal the reagent, holds mental content of card, 

 and "wills" the content to be projected into the mind 

 of the receiver. .After fifteen or twenty seconds he 

 taps twice to signal the close of the experiment, and, 

 when he notes that the reagent has recorded his guess, 

 himself records colour, number, and suit of the card 

 and number of the die determining the form -of the 

 experiment. When the die threw an even number the 

 experimenter ran ofT the rest of the experiment as 

 usual, but did not look at the card until the reagent 

 had recorded his guess, thus affording an effective 

 series of control experiments. The results of 10,000 

 guesses with University students, favourably disposed, 

 were entirely negative. No statistical analysis shows 

 any deviation in the percentage of right cases exceed- 

 ing the probable limits of pure chance, or any ten- 

 dency for the guesses to be more correct when the 

 reagent graded his answers high (indicating consider- 

 able confidence that they were right) than when he 

 graded them low. A further set of experiments was 

 made with ten "sensitives," five of them "spiritistic 

 mediums," persons WMth a sincere faith who gave time 

 and effort to the research without pay. The statistical 



1 Lelanrf Stanford Ttinlor Universiiy Piihlic.ntions. PsvrhVa! Research 

 MonoKranh No. i, " Experiments in Psychic.il R»sfarch at Teland Stanford 

 Junior University." Rv fohn Edear Coover, Fellow in Psychical Research 

 and Assistant Professor of Psychology. Pp. xxiv+fi^i. (Stanford University, 

 California, 1917.) Price, paper 3.50 dollars, buckram 4 dollars. 



