Ok, pearls are great- but since CZ wasnt around until 1976, why suspect it?
How much could you get for those things today? Just curious, I know several have talked about baseball cards and intellectually I know some are worth a lot (a million? more?) but I have no idea.
Here is a list of vintage stocks that you could potentially invest in (you can actually get better lists than this that shows complete trend analysis from that time to now).
Can you take an unsuspecting A/C back in your time machine to A/C your 1905 residence? 
Because in 1915 even if I didn’t know what it was, I could certainly tell you it’s not a diamond.
But, rarer than diamond. You might actually be able to sell it for a decent price, although bootstrapping demand for it would be problematic.
From the discussion so far, I’d say that gems/pearls sound like the way to go - portable, lightweight, have value in the proposed timeframe.
VG/NM copies of Action #1 have gone for over $1 million. A T206 Honus Wagner card in Ex 5 shape would fetch over a million as well. Take back a few ounces of gold, buy a bunch of baseball cards, then settle on a story to explain how you have them in the 21st Century. Although since you can make multiple trips, it might be a better idea to stash the cards, properly stored, somewhere you could “rediscover” them today.
Somebody had an air-conditioned home in 1914 without using time-travel.
How is any of that easier than just going back to yesterday and hitting a lottery?
Well, how to go back to the past and take stuff then become a modern millionaire has been done to death.
I think the gist of the Op is that you get to go back but not back & forth.
This is a much better and fresher hypothetical.
From what I can see, buying artificial rubies and such and cultured pearls is the thing- plus also buying a few thou in old bills as start up cash. $1000 in old bills will cost you no more than 10K, and be worth a lot more.
I actually had this same fantasy about going back in time to 1911 San Jose- what could I bring, could i survive, would I be happy?
Some people have mentioned dealing with the Spanish Flu. Would it be reasonably possible for someone today to get vaccinated against the Spanish Flu? It doesn’t look like it is common practice today, but are the barriers more practical, regulatory, or scientific? E.g. is it more that we just don’t need the vaccine, more that a Spanish Flu vaccine has not been approved by the FDA, or do we seriously lack the medical knowledge to actually produce one in 2015?
Each year they do a different vaccine and they say you need to do it every year. Thus I think that a standard 2015 vaccine would be almost worthless vs a 1918 flu. It appears that the 2009 flu pandemic vaccines might have been useful. But can you get that today? I mean, yes, they could likely make a vaccine today that would help, but why would they and how could you get it?
A anti-viral like Tamiflu might help, and also a antibiotic vs secondary bacterial pneumonias. Also Aspirin poisoning or salicylism was a issue, it is unknown how many died due to aspirin overdoses, but it was likely significant.
Was it evaporative, or did it use a refrigerant?
How much A/C does one need in Minnesota?
The “Spanish” flu is theorized to have begun in the USA. Unlike many other influenzas, it was especially devastating to young adults.
Since we are writing a practical how-to guide; it would be important to “lose” a few bets while building up the bankroll. If you are “too smart”, people might start to ask questions - with a baseball bat to encourage your answers. Also try to keep a low profile - no bragging, no ostentatious displays.
Own houses in Upstate NY - Saratoga, NYC - Aqueduct (sp?), Kentucky - Churchill downs, Florida, maybe Cuba. Move around with the seasons. Travel to Europe, just avoid the Titanic for the return voyage ;).
I’m not so sure about that. It’s a fascinating thing to speculate about, though.
Like most, I think I’d miss the PC, tablet, Internet, email, the Kindle and just modern books in general, movies on the home theatre, music on the sound system, real cars driving on real roads that actually get you places fairly fast, word processing (how the hell do you write a large document in 1915?), and probably much else.
But being rich, and knowing the future, would make up for a lot of it. Lack of modern conveniences would be much mitigated by a big service staff in your magnificent mansion, out in the fresh air and water of the countryside. You could take trips back and forth between Europe and America in first class suites on magnificent steamers. You could hobnob with the artists and writers in the left bank of Paris (Woody Allen did a fantasy movie about that called “Midnight in Paris”). You’d eventually become known for such prescience in your predictions and investments that you’d eventually have access to any famous person of the day you’d ever care to meet.
So I wouldn’t be the least bit concerned about how to maximize the money I took with me. Any amount would do – you’d make all your money there anyway. Just bring the relevant future information and don’t lose it!
What would probably concern me the most would be the lack of medical resources. You could die an early and miserable death and all they could do would be to pray at you. And it would take a while to get in step with their social conventions. I’d probably always be talking to someone that I wasn’t supposed to talk to because we hadn’t been introduced or it wasn’t proper for some other unfathomable reason, and wearing the wrong hat for the season and the wrong coat for the time of day. 
Even better, you can buy the 1914 $20 Federal Reserve notes in poor condition for under $40 each today. That’s the way to go.
For purly spending cash in 1915 I say go for Morgan Dollars. Plenty around, bulk poor condition ones can be bought now for probably around $20 retail, less if you put an ad on craigslist. Inflation adjusted 1 1915 dollar=23 2014 dollars…so not only do you have spendable cash (except for the 1921’s), but you profit at least $3 in purchasing power on each one. Oh and they are 90% silver and much more available/durable than paper money.
No it wouldn’t.
No, it wouldn’t!
If anything knowing the future would make you nuts. “Beer will get you through times of no money better than money will get you through times of no beer”. What good is knowing the future when all the money in the world won’t give it to you? I insist that no more than 6 months of banging flapper girls and the OP will be bored out of his mind, longing for 21st century home.
Even if the OP is only 30 in 1915 by the time anything even remotely close to what they’re used to comes around they’ll either be wayyyyy too old to enjoy it or wayyy too dead.
It really is a fascinating question. And I really think the answer isn’t that straightforward. I think there are many of us that would be absolutely enthralled to be back in that time, under those idyllic circumstances of wealth and privilege. And there are many of us – the technologist types – that would hate the technological primitiveness. But perhaps even those might adapt.
No question that the average person would be in terrible straits back then compared to now. But the really wealthy? Hmmmm…
And that got me thinking…
What if the social convention was being disrespectful to some minority group or treating women like chattel? Could you make yourself fit in? Would you live a happy life doing it?
In fact, what if you are a minority group member or woman?
You plan to play the horses? Do they even allow women in the betting room? Do they allow Negroes to enter the racetrack?
You want to invest in property or play the stock market? What if your banker or broker asks you to bring your husband or father along to sign the papers and “talk business”?
Things are far from perfect today, but social conventions are often uglier than just who to talk to or what clothes to wear.