Disclaimer: Don't own HP and Company. Harry's first lessons with Snape started with potions. This time with Snape making and explaining what the actual colors meant as the potion changed colors in the brewing process. A rich azure was surprisingly the sign of a potion gone wrong, while an ultra pale green was the sign an explosion was soon to happen.
The class held every Wednesday evening took them through November. Snape was calm and collected in these classes never being snide or sarcastic. In them Harry learned more then he ever did in the regular class on potions. Enough to get his grade up where it needed to be.
Harry continued his exploration of the castle with Hermione and Ron. One room they found in the library contained books that to Harry's eyes seemed to glow. When Hermione pulled one off the shelf she found the pages blank when Harry looked at it there were notes that seemed to pertain to transportation spells in a lovely Copperplate hand. A half dozen others where pulled out and examined. Blank pages for Hermione and Ron. Handwritten text for Harry.
Hermione grew thoughtful then exited the room and came back a few minutes later with a thick tome her finger marking a place. "This is a copying spell. It's used to copy a quote from a book to your essay. I don't know if it will work on the text that's invisible to us and make it visible. Try and copy one passage." Hermione ordered.
A blank sheet of parchment was set down Harry looked over the spell it was easy enough. He highlighted a paragraph in the book then attempted to copy it to the blank piece of paper. It worked. Hermione was able to read the text but it made no sense to her. Ron when he looked it over understood some. "The author have a name?" Ron asked.
Harry opened the book to the front. "Desmonda Fly," Harry replied.
"Wicked. She invited the Floo network over 200 years ago." Ron said.
"If all of these are hand written notes for inventions of one sort or another..." Hermione mused.
Harry put that one back and took out another book. This one he understood it covered potions. Another had charms of various sorts in them and one was a collection of jinxes Harry had never heard of he read out titles of the jinxes to the others. It was agreed that Harry would copy that one in its entirety for them. Even Ron didn't hadn't heard of them.
With Hermione urging caution when casting these new jinxes Harry showed them the old barracks room on the outer wall for their designated practice area. It took Harry a better part of a week to copy the book. Hermione went over each jinx first. It was she who picked out the first jinx for them to learn.
At this stage in their development magically they usually got the spell right the first time but it had a tendency to be a very weak version of it. The jinx Hermione picked used a very common counter to end the spell. Harry had drawn the short straw and was the victim of the jinx. Ron cast the spell and Harry's ears grew huge any movement over balanced him. Hermione cast the counter his ears returned to normal. It however was not a fast acting jinx it took some 2 minutes before the ears became unwieldy and another 2 minutes to reach maximum size.
Still it had a couple of advantages. Easy to cast with a common counter spell. They tried a couple more with the same counter spell. All had something to do with enlarging a body part or shrinking it. One jinx if aimed at the hands shrunk them so the victim couldn't hold a wand. Harry immediately saw the logic of that one and had Ron and Hermione promise not to use the jinx unless they where in mortal peril.
Harry returned to the hidden library within the main library several times he found books on all sorts of interesting things. One book he smuggled out of the library to take to his extra classes with Snape.
"Where did you get this?" Snape demanded after he had scanned the book.
"The library and it wasn't in the restricted section. There's a section of books that are blank to those with out Mage sight. Most of them are handwritten by former teachers who died here. Spell research and the like. Most of it is way over my head. A couple of the books are useful. There's one of just jinxes I copied it. The Author was the charms teacher before Prof. Flitwick. I'm only studying the ones with the counters I already know." Harry said. "There's a couple of them that I won't use unless I have to."
"Define won't use until I have to." Snape snapped at Harry.
"I'm in mortal peril." Harry replied.
"Acceptable I would also like to see this book of jinxes if you don't mind."
"The books are still in the room that is the only one I removed. Go to the section on domestic magic and go all the way back. There's a door there go inside and the books are there." Harry gave him the directions. "It's a normal door you just need mage sight to see it."
"Exploring the castle still?" Snape asked.
"Yeah, do you know that there is a pattern to how the stairs move in the square tower?" Harry asked.
"I am aware of it." Snape commented. "What do you perceive the pattern to be?"
"The person who is in the middle section determines where the stairs move to. Or if there is more then one person what house that majority belong to determines which way the stairs move. If it's a group but no majority the person the lowest in the middle section. Since all the staircases in that tower have 18 steps it's usually the person on the 7th step up from the bottom. Which is only wide enough for one person to stand on." Harry explained.
"Close there are a few other factors that determine movement for those stairways that you missed. For the most part though you have it right." Snape commented. "I'll inform the other heads of house about this room of books. It may be simply that since mage sight is needed to see the door it was considered secure enough as it is a very rare child who has mage sight. If I may ask what prompted your bring this to me?"
"Theory of magic we're covering the disasters of spell use with out knowledge of a safe means of undoing the spells." Harry replied. "Then there are the Weasley twins in my house."
"Ah. They experiment on the younger years?" Snape asked curious.
"On themselves. Everything they try on the others already has a counter." Harry replied. "I also think their mage sight is beginning to come in."
Snape looked at the book in his hand while it is not on anything he would consider dark the spells and potions in the book where definitely in the grey area and he's already noticed a tendency for the Weasley twins to use some grey ingredients in their concoctions. Nothing that would land them in jail but enough to raise flags.
The room of notebooks in the library proved very interesting. Flitwick was pleased with the finding of his predecessor's research notes on various charms and jinxes. The book of jinxes Harry had found had been common when Flitwick was a student at Hogwarts. The hand shrinking jinx wore off fairly quickly on its own. He pronounced the book fairly harmless and since most of the spells had fallen out of use over a century ago it would be a good collection of defense spells for Harry and company since most where easily cast by fourth years.
Professor Flitwick did join Snape and Harry at one of the Wednesday classes to go over the book. It proved to be an interesting class. The hidden library was gone over by each of the Heads of house and the books deemed dangerous removed. That proved to be only a handful. The others where left were they where and no extra security was added.