"My dear sir," cried Holmes, "there cannot be the least doubt in the world that it has been written by two persons doing alternate words. When I draw your attention to the strong t's of 'at' and 'to' and ask you to compare them with the weak ones of 'quarter' and 'twelve,' you will instantly recognise the fact. A very brief analysis of those four words would enable you to say with the utmost confidence that the 'learn' and the 'maybe' are written in the stronger hand, and the 'what' in the weaker." "By Jove, it's as clear as day!" cried the Colonel. "Why on earth should two men write a letter in such a fashion?" "Obviously the business was a bad one, and one of the men who distrusted the other was determined that, whatever was done, each should have an equal hand in it. Now, of the two men it is clear that the one who wrote the 'at' and 'to' was the ring-leader." "How do you get at that?" "We might deduce it from the mere character of the one hand as compared with the other. But we have more assured reasons than that for supposing it. If you examine this scrap with attention you will come to the conclusion that the man with the stronger hand wrote all his words first, leaving blanks for the other to fill up. These blanks were not always sufficient, and you can see that the second man had a squeeze to fit his 'quarter' in between the 'at' and the 'to,' showing that the latter were already written. The man who wrote all his words first is undoubtedly the man who planned this affair." "Excellent!" cried Mr. Acton. "But very superficial," said Holmes. "We come now, however, to a point which is of importance. You may not be aware that the deduction of a man's age from his writing is one which has been brought to considerable accuracy by experts. In normal cases one can place a man in his true decade with tolerable confidence. I say normal cases, because ill-health and physical weakness reproduce the signs of old age, even when the invalid is a youth. In this case, looking at the bold, strong hand of the one, and the rather broken-backed appearance of the other, which still retains its legibility, although the t's have begun to lose their crossings, we can say that the one was a young man, and the other was advanced in years without being positively decrepit." "Excellent!" cried Mr. Acton again.