balcony,’ replied Carstairs. ‘I have been looking at it from below, and also out of the bathroom window, and I am certain that a person possessed of a clear head and average muscular development would find no difficulty in climbing from the iron railing of the small balcony outside the bedroom which is occupied at present by Miss Clark to the window of the bathroom where the crime was committed. If the window was open at the top to let the steam out, the murderer could have opened it at the bottom, for it is just an ordinary type of sash window, and slides up and down extremely readily, I noticed. Once the stepping from the balcony was accomplished and the bottom of the window pushed up, it would be simplicity itself to climb in over the sill.’
‘Oh, nonsense!’ snorted Alastair Bing, ‘it is too hideously dangerous an undertaking for words. No sane person would dream of attempting such a feat.’
‘No sane person——’ Carstairs blinked, as a newthought occurred to him. He shrugged his shoulders, and went on more briskly:
‘Look here! We can soon settle whether it is a possible or an impossible feat. You go up to the bathroom and look out of the window, and I’ll get someone to attempt the climb.’
‘I won’t have anybody take unnecessary risks,’ retorted Alastair, with spirit.
‘Very well. I’ll do it myself!’ And Carstairs made his way to the door and passed out. Alastair Bing, pulling irritably at his bristling moustache, followed him.
‘The bathroom! Let us have another look at the bathroom!’ he cried.
It was like all other bathrooms—bare, tiled, sunny, and austere.
‘The window was open like this,’ said Carstairs, pushing the top of it down some four inches.
‘As much as that? I don’t remember noticing it myself.’
‘Oh, yes. Quite as much. And the bottom was right up like this.’
He pushed it up so that an aperture large enough for a well-grown man to obtain admission from without was disclosed.
‘Yes, I remember that,’ Alastair assented. ‘I thought at the time it was odd that anyone should be having a bath with the window wide open like that. One could be seen from the garden and the stables as soon as one stood up, I should imagine.’
‘Quite,’ Carstairs agreed. ‘So the murderer musthave opened the window, I should say; the victim would not have done so.’
‘Of course, the great objection to your theory of murder is that no marks of violence or evidence of poison have been discovered on or in the body,’ Alastair pointed out.
‘Of course they have not!’ Carstairs stared in amazement. ‘Mountjoy was drowned!’
‘Drowned! But, my dear fellow, people don’t allow themselves to be drowned as easily as all that.’
‘Don’t they? Have you ever heard of the “Brides in the Bath” case?’
‘I—yes, I suppose so. Yes, of course I have. A dreadful scoundrel, that man.’
‘Yes. Look here, Bing, take off your coat and get into the bath. It is quite dry, so you need not be afraid of spoiling your suit. Just a moment, though. One question. Which of us two do you take to be the stronger man?’
‘Myself, undoubtedly,’ replied Alastair, without hesitation. ‘I am both taller and heavier than you are.’
‘And you do your exercises regularly, I’ve no doubt, whilst I meander around after my flora and fauna. Well, that only lends more colour to my argument. Come, get in. This is not a practical joke. It is a serious demonstration.’
Unwillingly Alastair Bing divested himself of his jacket and boots, and, feeling extremely foolish, stepped into the bath.
‘Sit down,’ commanded Carstairs vigorously.
Protesting against a waste of time, but interested in spite of himself, Alastair obeyed.
‘I sit here on the edge of the bath. I am talking to you on a subject very near to my heart. It is a subject which vitally concerns both of us, so much so that I have even climbed through the window in order to interview you in your bathroom, where,