258 REPORT ON THE STATE OF SCIENCE, ETC. 



to arrive at a reasoned conclusion with regard to the opposed views of the nature of a 

 sy clonic depression. 



The Committee accordingly asks for reappointment with the addition of the name 

 :>f Mr. L. F. Richardson, F.R.S., and for permission to retain the grant of £70 made 

 iast year to defray the expenses of a co-operative investigation. 



Problem : To find the cheapest way of filling ' Post Card Balloons ' simul- 

 taneously. One at each of 100 places scattered over the British Isles. 



Purity of hydrogen and accuracy of adjustment of lift have been regarded as of 

 secondary importance. The following process has been found to work well. 



Apparatus. — -Balloon weighing 5*5 grams empty. Tinned-iron can of capacity 

 580 cm. 8 with air-tight lid through which is soldered a brass pipe of external diameter 

 09 cm., so as to project 6 cm. outside the can and 1 cm. inside. Carton cup holding 

 140 cm. 3 (sold for holding preserved cream). Calcium hydride of Messrs. J. J. Griffin's 

 (Kemble St., Kingsway, London, W.C. 2) cheaper quality, Is. per oz. Bucket of cold 

 water. Teapot or small jug with spout. Post card. Thin cotton string. Balanoe 

 weighing to 0.1 gram. 



Working Instructions. — Slip the neck of the balloon 1 cm. on to the brass pipe and 

 tie in place. Weigh out 12-5 grams of hydride in lumps, rejecting powder, as it so 

 rapidly spoils in damp air. Dry the canister internally and put the hydride into it. 

 Lower the carton cup into place and fill it with water from the jug, taking care not 

 to spill any water on hydride. Press the lid into place. Now slightly tilt the canister 

 so as to spill a little water on the hydride. To prevent a high temperature float the 

 canister in water in the bucket. If the balloon fills lop-sidedly it may often be made 

 symmetrical by squeezing the bloated side. Continue the tilting and shaking until 

 all the water is spilt and no more fizzling can be heard in the canister. The balloon 

 should then be about 30 cm. in diameter, and is ready to be tied at the neck after 

 the manner of a football bladder. 



Suggestions for Organisations. 



The vendors of the calcium hydride might be persuaded to supply it ready weighed 

 in sealed glass tubes, each containing just enough for one balloon. The canisters and 

 cartons should be got ready by a firm and distributed by the firm to the observers. 



Estimate of Cost in Pence. 



1st Ascent. d. Subsequent Ascents. 



Post card 



Balloon .... 



Hydride .... 



Canister .... 



Supplying and soldering pipe 



Carton .... 



Carriage . . . . . 12 ? 



1* 



3 [ lOid. each. 



6 

 4 



6? 

 2? 



r 



Total . 34| ? 



Other Methods, Rejected, and the Reasons for Rejecting them. 



1. Aluminium and NaOH in the same apparatus. Dangerous, for caustic froth 

 entered balloon, and might be thrown in the operator's eyes if balloon burst. Calcium 

 hydride and water is much less frothy and less caustic. 



2. Cycle lamp as generator. Difficult to get the necessary pressure because the 

 water vessel leaked. 



3. Purchase of hydrogen gas compressed in cylinders. Conversation at British 

 Oxygen Co.'s office indicated, without commitment, that their smallest size of cylinder 

 contains 10 cubic feet of hydrogen. They have about 50 of these and would lend them 

 free for a fortnight. The hydrogen would cost about 12£d. per cylinder. The charge 

 for carriage is probably more and is difficult to estimate. (Cylinders are class 3 on rail.) 

 For instance, King's Cross to Newcastle-on-Tyne would be 2/2 by goods each way. 

 Carriage would be reduced by distributing from Glasgow, Wolverhampton and London, 

 whichever was nearest. 



Objections : Carriage ; doubt as to whether enough cylinders ; rent of cylinders 

 if kept too long. 



