274 



NATURE 



[May 15, 191; 



O'Gorman : Instruments for aeronautical work, 

 and research on aeroplane stability. (1) Ripograph : 

 to record velocity, roll, pitch, yaw, and the correspond- 

 ing movements of the flyers controls on a continuous 

 photo-strip. (2) V'elometer : to indicate speed through 

 the air of aeroplanes and airships. (3)' Trajectograph : 

 to record the path through the air of aeroplanes. (4) 

 Air distance recorder or log : to give miles passed 

 through the air of aircraft. (5) Recording accelero- 

 meter. (6) An airship and aeroplane instrument 

 board complete. (7) Tautness meter : to enable the 

 pull on a wire to be measured without altering or 

 cutting it, or putting fixtures on the wire. Suit- 

 able for using during flight. Mr. J. D. Fry : 

 A micromanometer capable of detecting differ- 

 ences of pressure of the order of one-millionth 

 of a millimetre of mercury. The difference 

 of pressure to be measured is applied to the two sides 

 of a stretched membrane ; the centre of the membrane 

 bv its displacement twists a mirror which is sus- 

 pended in a special manner, the pressure differences 

 being indicated by the deflection of a spot of light. 

 National Physical Laboratory: Apparatus for the 

 rapid determination of the lifting power of samples 

 of hydrogen. (Mr. Guy Barr.) The method employed 

 depends on the principle of balancing columns com- 

 monly used for comparing the densities of liquids. 

 From the reading of a gauge, when the pressure 

 difference is balanced, the lifting power of the hydro- 

 gen is determined with an accuracy of about 002 per 

 cent. From the lifting power the purity of the 

 hydrogen may be deduced by making corrections to 

 N.T.P. after observation of the volume of a known 

 mass of air. 



The Cambridge Scientific Instrument Company, 

 Limited: (1) Apophorometer : an instrument de- 

 signed by Prof. J. Joly, for easily obtain- 

 ing sublimates from substances at high temperatures. 

 (2) Rack barometer : a barometer of the marine type, 

 in which a dial is substituted for the vernier in general 

 use. The dial is divided to read directly in tenths 

 of a millibar. (3) Stomatograph : an instrument 

 which records the amount of opening of the stomata 

 on a leaf. (4) Yaw indicator : this instrument is 

 designed to indicate the direction of a cur- 

 rent of gas in any plane. M. C. V. Boys : 

 Rainbow cups — old and new patterns. The chief 

 characteristic of the new pattern is the point 

 support of the cup. The accurate work neces- 

 sary with an axle is avoided and the friction is 

 greatlv reduced. The cup supported at a point is 

 free to precess, and during this motion the 

 coloured rings appear to expand and contract 

 in time with the precession. The direction of 

 precession is opposite to that of an ordinary top. 

 Sir John Thornycroft : Model to illustrate the effect 

 of a compound cross sea on vessels of various rolling 

 periods. In the model a plane surface is supported 

 on three points, two of which move vertically and 

 the third is stationary. In the vertical motion of each 

 of the two moving supports four simple harmonic 

 motions are combined, and the phase of motion in the 

 two differ bv a quarter of their time period, and 

 produce in the moving surface a symmetrical motion, 

 resembling that of a small portion of a complicated 

 sea in which similar waves are crossing at right angles. 

 Mr. R. E. Gilhnor : The Sperry gyro compass. To 

 be efficient the gvro compass must be so suspended 

 that there is almost an entire absence of friction about 

 the vertical axis, while at the same time forces must 

 be impressed upon the wheel itself about the hori- 

 zontal and vertical axis to cause the wheel to rotate 

 into the plane of the earth's rotation. In the Sperry 

 compass both are accomplished by suspending the 

 gyroscopic or sensitive element from a stranded wire, 

 NO. 2272, VOL. qi] 



the top of which is held in a frame surrounding the 

 sensitive element and made to follow it by a system 

 of electrical contacts controlling a motor which drives 

 the frame. 



Underfeed Stoker Company, Ltd. : C0 3 thermo- 

 scope, a self-contained pocket instrument for the 

 thermometric analysis of carbonic acid gas in furnace 

 and other gases. The instrument operates by measur- 

 ing the heat of reaction between CO, and dry pul- 

 verised caustic alkali. (See Nature, April 17, p. 171.1 

 Mr. F. W. Jordan : Convection radiometer and 

 thermo-galvanometer. This instrument is primarily 

 intended for the measurement of feeble steady 

 rates of evolution or absorption of heat. Mr. 

 Dugald Clerk : Determination of the volumetric 

 heat of air, carbon dioxide, nitrogen, and flame in 

 the cylinder of the internal-combustion engine. The 

 volumetric heats of various gases and flames have 

 been determined by the method of alternate compres- 

 sions and expansions described in a paper read before 

 the society in 1906. The present investigation deals 

 with gases at low and high temperatures, and gives 

 values between ioo° C. and 1000 C. Laws of cool- 

 ing have also been investigated, and the remarkable 

 effect of turbulence on the rate of flame propagation 

 in engines has been demonstrated. Prof. Leonard 

 Hill : Kata-thermometers or comfort-meters. Two 

 largre-bulbed spirit thermometers are used. The 

 bulb of one is surrounded with muslin. The 

 stem of each is marked with heavy black lines 

 at 110 F., ioo° F., and go° F. Readings can be 

 taken with the bulbs of the instruments (1) clothed ; 

 (2) exposed or shielded from radiant heat, e.g. a. fire. 

 By this means the heating and ventilation of rooms 

 and the effect of clothes can be investigated and 

 arranged so as to give (1) comfortable loss of body 

 heat ; (2) prevent depressing effect of uniformly 

 heated air on cutaneous nerves. Prof. L. R. 

 Wilberforce : Experiments with ripples. Ripples 

 produced on a water surface by a vibrating 

 dipper are projected by intermittent light so as to 

 appear stroboscopically in slow motion. A phonic 

 wheel drives the slotted disc which produces the inter- 

 mittence, the motion being transmitted by fluid fric- 

 tion whereby a very uniform rotation is obtained. 



Mr. E. Leitz : Ultra-condenser for the observation 

 of ultra-microscopic particles. The ultra-condenser 

 has been devised for ultra-microscopic observations, 

 especially in the examination of fluids and gases. The 

 condenser renders any ordinary microscope suitable 

 for the purpose. It consists of two glass bodies, each 

 having a reflecting spherical surface, cemented into 

 a metal box fitted with a bayonet-jointed and rubber- 

 faced coyer. The cover is fitted with a disc of quartz 

 which serves as a cover glass. Underneath, the cover 

 glass has a cavity for receiving the liquids and gases 

 for examination. The condenser is not intended for 

 high-power observations, and therefore objectives of 

 shorter focal length than 8 mm. may not be used. 

 Prof. J. Norman Collie and Mr. H. S. Patterson : 

 The presence of neon and helium in hydrogen after 

 the passage of the electric discharge through the latter 

 at low pressures. Whatever the explanation may be 

 of the presence of neon and helium in hydrogen after 

 the latter has sparked it seems to be certain that : — 

 (1) Neon and helium cannot be obtained from either 

 glass or from the electrodes by heating alone; (2) 

 glass, when heated to near its softening point and 

 subjected to the action of kathode rays, is not per- 

 meable to neon or helium, so neither neon nor helium 

 diffuses into the apparatus from the atmosphere. 

 Mr. A. Fowler: New lines in the spectrum of 

 hydrogen. Certain lines which occur in the spectra 

 of stars and nebulae have been attributed to hydrogen 

 by Pickering and Rydberg in consequence of numerical 



