DISCOVERY 



Flying Through a Monsoon Storm 



Before we reached Agra we ran into another of the 

 terrifically dense monsoon rain-storms. Afterwards 

 we found that five inches of rain fell in a few hours. 

 Our engine again developed trouble, and we landed 

 before it actually " cut out." The propeller fabric 

 had been stripped off by the rain, and lumps of wood 

 were eaten out of the edges of the propeller. On 

 inspection it was found that it was hopeless to try 

 to continue with the engine as she was, and for a time 

 I was somewhat at a loss as to how to proceed. 



Fortune favoured us this time. I was told that the 

 Maharajah of Bharatpur, who lived some thirty miles 

 away, had a number of aeroplanes of exactly the 

 same type as that which we were using. He lent 

 us an engine, and his mechanics installed it. 



At Agra, which we had reached on 5th August, 

 I was overtaken by illness and was carried to hospital 

 suffering from appendicitis, but despite the advice of 

 the authorities, I decided to push on to Calcutta and 

 prepare things for the next stage of our journey. 

 Shortly after my arrival Macmillan and Malins arrived, 

 having made the journey from Agra via Cawnpore, 

 Allahabad, and Gaya in two days. This was the 

 end of the first stage of oar flight. We had covered 

 over 10,000 miles by air, and had flown over some 

 extremely bad country under the worst possible 

 conditions. Among other things, we had flown the 

 Mediterranean from Athens to Solium on a land 

 machine — a feat never previously attempted — and we 

 had crossed India during the worst part of the heaviest 

 monsoon in living memory — a thing said to be 

 impossible. 



The Final Disaster 



Whilst I was in hospital recovering from my opera- 

 tion, Macmillan and Malins left on our second machine, 

 the Fairey seaplane, bound for Rangoon. An airlock 

 forced them to descend in the Bay of Bengal, and 

 they floated about for two days and three nights 

 before they were rescued on 24th August by Lieut. - 

 Commander Cumming, who had been sent out from 

 Chittagong to search for them. Their experiences 

 were terrible. It was only due to the fact that clouds 

 obscured the sky and rain fell most of the time that 

 they got through alive, but had the rescuing tug 

 arrived half an hour later it would have been too 

 late, for the machine broke to pieces almost as they 

 left it. 



Though we did not succeed in our object, we gained 

 a great deal of experience in flying over this part of 

 the world, and hope that next year, if all goes well, 

 we shall be able to carry out what we attempted. 



Pencil Pigments in 

 Writing 



By C. Ainsworth Mitchell, M.A., F.I.C. 



The examination of pencil pigments in writing has 

 not until recently attracted the attention that has 

 been paid to inks, doubtless because it was regarded 

 as unpromising. Actually much less can be deduced 

 from pencil than from ink marks, but such facts as 

 emerge are not without interest. 



Schonemann mentions, in a curious book of his pub- 

 lished at Leipzig in 1818, that codices of the eighth 

 and ninth centuries contained vertical parallel mark- 

 ings made with a stylus, whilst from the eleventh 

 century onwards these lines were ruled in black lead. 

 Now graphite (black lead) was not discovered, or at 

 least used as a pigment, rmtil 1566, so that apparently 

 Schonemann must have mistaken markings in m.etallic 

 lead for graphite. 



The microscopical appearance of lead and its alloys 

 is quite distinct from that of graphite, the lines show- 

 ing a disconnected series of patches irregularly distri- 

 buted and uniformly and brilliantly lit up, and each 

 patch is marked with regular vertical striations. This 

 is shown in Fig. i. 



I called attention to this apparent anachronism in 

 Schonemann' s observations in a communication to 

 Nature (1920, 105, p. 12), and this drew from Professor 

 Flinders Petrie a reply that he could give me a portion 

 of a fragment of graphite which he had discovered 

 in a tomb at Ghorub, in Egypt, and which must have 

 dated back to a period between 1500 and 1200 B.C. 

 This specimen of graphite, for which I am indebted 

 to the kindness of Professor Flinders Petrie, is decidedly 

 impure, containing only 39-4 per cent, of carbon, 

 and a very high proportion of siliceous impurities. 

 Its full analysis was recently brought before a meeting 

 of the Society of Public Analysts (see The Analyst, 

 1922, 47, September). 



In view of this discovery of the existence of the 

 mineral centuries before graphite was reputed to be 

 known, I decided to examine early MSS. in this 

 country, and I have to thank Bodley's librarian and 

 Dr. Craster for giving me facilities to study similar 

 specimens of pencil markings in the Bodleian Library. 

 The results of my examination, which are recorded 



' An article by the same author on Ink Pigments in 

 Writing appeared in Discovery for last December. In 

 connection with this article it is interesting to note that in 

 the ;^640,ooo will suit, settled on November 14 last year, 

 Captain W. E. Foster and others successfully contended that 

 pencilled alterations of certain documents were legal testa- 

 mentary depositions. — Ed. 



