MR. COTTENHAM was unable to show them the experiments he had promised, as he was engaged all the evening, so they went home after tea. A week later they again went to see him.

“I was very sorry, Walter,” he said, “to disappoint you last week; but I have everything ready this time.”

“Take care!” said the parrot; “wipe your boots!”

“A very good hint!” laughed Mr. Cottenham.

As it was a lovely April day, and quite warm, they had tea in the summer-house. Mr. Cottenham was very proud of his garden, in which he spent most of his leisure time, working very hard to keep it tidy and full of the best flowers of the season. There were already many flowers in bloom, and the view across the river towards the grand old cathedral was very fine.

“Steve,” he said, when they were about to sit down to tea together—Poll was also there, and Alfred had gone to fetch Rover, the big dog, from his kennel—“Steve, when I was in the old book-shop, looking at some works on gardening, one of your boys came in; his name, I think, is Cox; his father is agent for an insurance company. He is about your height, and has red hair.”

“Yes, sir, that is Harry Cox,” replied Steve.

“What arithmetic do you use?”Steve named the book they used.

“Alfred told me all about the trouble he got into with Mr. Harmer, when he found a page of answers to his sums in his exercise book,” said Mr. Cottenham. “When I heard a boy ask for an arithmetic book with answers, and saw that it was one of your boys, I noted what occurred. Mr. Thrupp, the bookseller, found him a copy, and told him it would be two shillings. It was a second-hand book. He bought it and took it away with him. I did not say anything, but you, Walter and Steve, should watch and see if his sums are right now.”

“We will, sir,” replied Walter, “and we are much obliged to you for telling us. I think either he or Herbert King put the answers in Alfred’s book to spite him.”

“Don’t say a word to Alfred until you are sure about it; but I thought if I told you, it might lead to the discovery of the boy who used the answers. Here comes Alfred with Rover.”

Rover came in, jumping about, and threatening to break all the cups and saucers, until his master told him to lie down. Poll amused itself by whistling and calling the dog, but after the first time Rover was not deceived, and merely looked at the bird as if he wondered how it did it.

Mr. Cottenham always had plenty of anecdotes to tell the boys of his adventures in India, as he had been a keen sportsman and crack shot. He was now an officer in the local volunteers, and by far the best shot in the regiment.

“You promised once, sir,” said Steve, “to tell us an anecdote about a tiger-hunt you once had in India.”

“Did I?” replied Mr. Cottenham; “then I must keep my word. I shall never forget that adventure. Although it was very dangerous, it was also very funny, and I believe I laughed more than I trembled at the time. I was in charge of one of the government stores in a distant part, where there were but few Englishmen, although there was a regiment of native infantry and a squadron of cavalry.

“Our work up there was much the same day after day, so I was as much excited at the prospect of a change as you are. The captain in command of the cavalry came in one morning and asked me if I should like to join him in a tiger-hunt. A large tiger had been seen in the neighbourhood, and had carried off a lot of cattle and a horse. He said he had sent some mounted men out to scour the country, to see if they could find out where the animal was. I told him I should be delighted to join him as soon as I had finished my official duties. I had a large store-room, in which the drugs were kept, and amongst them, some large bottles of ammonia. I suppose you know that ammonia is very strong smelling, and is used in smelling-salts.”

“You put some in the pigeon’s milk, didn’t you, sir?” inquired Alfred, laughing.

“I did, Alfred. Well, I was busily engaged in looking over the stores and making up some medicines; but I was thinking about the hunt we were going to have rather than about the work I had in hand. My native servant was occupied in getting both my guns ready, and my horse as well, as I hoped in an hour to be able to join the captain, who was about to start. He called, on horseback, and told me where the tiger had last been seen, and asked me to come to him as soon as possible. I told him I would, and I hurried on with my work, just as you boys do when you have a holiday directly it is finished.

“I had to go into the large warehouse at the back of the store for some drugs. The warehouse had four small windows and one door only, which I always kept locked, as I had had many goods stolen. It was very hot, and when I was in the warehouse I was so warm that I sat down for a few moments on some mats, just to cool myself and write down a few notes in my book. I suppose I must have fallen asleep almost immediately, as I woke with a start and recollected the hunting expedition. I looked at my watch, and you may imagine my surprise and disappointment when I found that I had been asleep nearly two hours. I felt very cross with myself, as I had never yet had an opportunity of joining in a tiger-hunt. I longed to see the ferocious animal in his wild native state. So I got up, and was about to finish my work, when I chanced to glance towards the doorway. There, in the cool shade, stretched quite at his ease, lay a huge tiger!

“I had no weapon, and it was quite impossible for me to get out of the outhouse without walking over the savage beast. All this flashed through my mind in a moment. If I shouted I should arouse the tiger, which would in all probability immediately attack me. I was quite defenceless, and my only hope of safety lay in being absolutely quiet. You may rest assured I did so, hoping that my servant might chance to come round and see where I was; but, as I had told him he could join the hunt directly he had got my guns and horse ready, I had little hope of that. I suppose that the animal must have been hunted by the captain and his followers, and, being tired, had selected that spot for repose. There were several big boxes behind which I had been lying, so I was hidden from the tiger’s view. My store was outside the village, and stood alone, so that the tiger was not disturbed. I need hardly say I could not take my eyes off the beast, which was apparently fast asleep. I waited for quite a quarter of an hour, silently watching my uninvited guest, when suddenly I saw a large bottle which was labelled Liquor AmmoniÆ Fortiss. You know sufficient Latin to understand that fortiss, is the abbreviation for strongest. Noiselessly I took this big bottle and put it on a box in front of me. Then I found a small pan, filled it with the strong ammonia, and hid myself again behind a big box. The breeze carried the strong odour towards the tiger’s nostrils, and the animal was aroused in a moment. It sniffed and jumped up, and then sniffed again, as if undecided what to do. It went up to the pan and took one sniff at the liquid, then bounded out of the shed as if it had been shot. I could hardly help laughing at his sudden disappearance. I ran quickly into the store and got both my guns, mounted my horse, and went in the direction in which I had seen the tiger rush. A few minutes later I met the captain returning, without having seen the tiger he had been hunting for. In a few words I explained what had taken place, and away we went after my old friend. Well, boys, to cut a long story short, I had the good luck to shoot the animal myself, and you must have seen the skin hanging up in my parlour.”

“Is that the very same, sir?” asked Steve. “It is a very big one.”

“Yes, Steve, and it looked much bigger when alive and lying in that doorway, I can assure you. Why, boys, you have not been eating and drinking while I have been talking. What has become of your appetites?”

Thus reminded, the boys did ample justice to the food, and after tea they went into Mr. Cottenham’s laboratory—that is, the room in which he made chemicals or did chemical experiments. Walter eagerly followed everything he said and did. Mr. Cottenham explained in a very clear way all the changes that took place. He took a glass jar, called a beaker, and put into it a white powder, which, he said, was called sugar of lead or acetate of lead. This powder he dissolved in some water, tied on to a string some pieces of zinc, and fastened the other end of the string to a glass rod, which he placed across the top of the beaker. He left this while he was doing some other experiments, and there was gradually formed, on the string, a bright, leaf-like structure, called a lead-tree. He explained to Walter that the zinc had changed places with the lead, and was in the liquid, while the lead was on the string. He took a glass-tube, called a test-tube, and put into it some more sugar of lead dissolved in water, and then he took some little whitish crystals of iodide of potassium, and mixed the two liquids while warm. When the mixture was cool there were beautiful crystals, just like gold, glittering and yellow. These, he said, were iodide of lead.

“When I was in India, boys, I made a quantity of this to amuse myself; and to have a joke, I put a lot of these crystals in the sandy soil by the side of a small stream, where the natives often came for water. I stood at a distance and watched for a short time, when a terrible hubbub was raised. There were the men, women, and children squabbling and grabbing this gold, as they thought. In one of the papers it was afterwards said that a quantity of gold had been discovered, and an engineer and some government officials came to investigate. I need hardly say that no gold was found. I did not tell them how the report had got circulated. I suppose, boys, I am rather fond of spinning yarns.”

“What’s that, sir?” innocently inquired Alfred.

“Why, Alfred, that means telling short stories.”

“We like them ever so much,” said Alfred, “and we shall remember what you tell us better, because we can’t forget your stories—yarns, I mean.”

Amongst several other experiments which Mr. Cottenham performed was one in which he took some powdered sugar and some other white powder, called chlorate of potash, moistened a rod in an acid (oil of vitriol) and touched the mixed powders. Immediately they caught fire, and all the powder turned black.

“Mind, boys, that you always wash your hands after touching any chemicals, as many of them are poisonous, and also, never do any experiments without first asking, as some things explode, and might seriously injure you. I had an accident when I was a boy, through being too conceited to ask. I thought I knew everything, and so I made some gas (it was hydrogen), and lit it without taking the proper precaution of seeing that there was no air left in the flask. Immediately there was a loud report like a pistol-shot, and my apparatus was blown all to pieces. You see that scar just above my eye. Well, that was where a piece of glass struck me, and I am thankful that I did not lose my sight. Boys too often think that making an explosion is a big joke, but it is also a very dangerous one.”

“Do you teach chemistry, sir?” inquired Alfred.

“Yes, at the grammar-school, and I am going to ask Mr. Harmer to let me give you a course of lectures at your school next autumn, similar to those I give at the grammar-school.”

“Please do, sir!” exclaimed Walter; “and let me help you with the experiments.”

“That I certainly will, Walter, as it is a pleasure to teach you chemistry, you take such an intelligent interest in all I do here.”

“What is that for, sir?” inquired Steve, pointing to a very complicated piece of apparatus.

“That is for water analysis,” replied Mr. Cottenham. “I am the borough analyst, and have to test the milk, butter, and anything else that may be brought to me.”

“I should like to be a chemist, sir!” exclaimed Walter. “I hope that when I leave school father will let me be one.”