Page. 186
「おお、エミールよ！ お前の ためにも、兄さんは 安全な 爆薬を 作って 見せるぞ。」
“Oh Emil! For the sake of my brother, I will see that a safe explosive is made.”
悲しみの 中、ノーベルは ちかいました。
Nobel swore in his grief.
研究室に とじこもり、夜も ねないで 実験を くりかえす 日び。
He did not sleep and shut himself away every night and day in the laboratory to repeat experiments.
p. 186
「おお、エミールよ！お前のためにも、兄さんは安全な爆薬を作って見せるぞ。」
“Oh Emil! For your sake, your older brother will produce a safe explosive.”
Is みせる something in the line of “watch your older brother as he will produce ….”?
悲しみの中、ノーベルは誓いました。
Nobel swore in his grief.
研究室に閉じこもり、夜も寝ないで実験を繰り返す日々。
Day after day he secluded himself in his laboratory, repeating experiments without sleeping at night.
Yes, we’ve seen that a lot in this book.
I found this reference from Tae Kim that confirms what you’ve said about おり being used rather than い when using いる as a verb stem for continuation. It also gives a couple of examples. Last two to three paragraphs of the article.
There are two meanings of て form followed by みせる. Here it demonstrates a determination to carry out an action, like “I’ll show you!”.
Quoting from this reference:
～てみせる ( -te miseru ):
A -te form verb plus みせる ( miseru ) has at least two possible meanings. One directly draws on the literal meaning of 見せる ( miseru , to show), and refers to performing an action so that it will be seen, or putting it on display, sometimes purely for appearances.
The other meaning uses perhaps a looser usage of “show” and indicates a determination to carry out an action. It has something of a sense of “I’ll show you!” This meaning is less likely to use the kanji.
p. 187
やがて、ついにーー。
Eventually, finally …
《そうだ！ニトログリセリンの水分を、土のような物に染み込ませて固くしたら、安全にもちはこべるはず。これはいけるぞ！》
“That’s it! When the liquid of nitroglycerin is soaked with a clay-like substance and hardened, it can be safely carried. This may work!”
『ダイナマイト』の誕生でした。
That was the birth of “dynamite”…
ダイナマイトは、今までの爆薬に比べ、パワーも強く、持ち運びも安全でした。
Dynamite, compared to previous explosives, was more powerful and safer to carry.
そのため世界中の国や会社に喜ばれ、大人気なりました。
Hence in countries and companies throughout the world, it was gratefully accepted and became very popular.
Pg. 187 (2 more to go! 
)
やがて、ついに―――。
Before long…
《そうだ！ ニトグリセリンの 水分を、土のような ものに しみこませて かたく したら、安全に もちはこべるはず。これは いけるぞ！》
That’s it! If you take nitroglycerine’s liquid part and soak it into something solid like earth, you should be able to carry it safely. This can work! (?)
『ダイナマイト』の たんじょうでした。
Dynamite was created.
ダイナマイトは、今までの 爆薬に 比べ、パワーも 強く、 もちはこびも 安全でした。
Dynamite, compared to other explosives until then, was stronger in power and safer to carry.
そのため 世界中の 国や 会所に 喜ばれ、 大人気となりました。
Because of that it became popular with counties and companies worldwide.
１８５：
こうして ノーベルは、お父さんの 仕事を 手伝ううちに、爆薬を 研究するように なったのです。
Thus Nobel, while helping with his father’s work, was studying explosives.
そのころの 爆薬は、「ニトログリセリン」という 液体から できており、少し ゆれただけで すぐ 爆発してしまう おそれが、ありました。
In those days, explosives were made from a liquid called nitroglycerin, there was a fear that with just a little shake it would explode.
ノーベルは 心配していましたが、ある日ーー。
Nobel worried until one day…
ノーベルの 工場で 爆発が おきました。
An explosion occurred at Nobel’s factory.
工場の 中には、弟の エミールが !..
Among those at the factory, Nobel’s little brother Emil!
エミールは 爆薬の ぎせいに なってしまったのです。
Making Emil a victim of explosives.
１８６：
「おお、エミールよ！お前の ためにも、兄さんは 安全な 爆薬を 作って 見せるぞ。」
Oh no, Emil! For your sake, I will make and display a safe explosive.
悲しみの 中、ノーベルは ちかいました。
Filled with sadness, Nobel vowed.
研究室に とじこもり、夜も ねないで 実験を 繰り返す 日々。
Secluded in the laboratory at night without rest, he repeated experiments daily.
１８７：
やがて、ついにーー。
Until finally…
〈そうだ！ニトログリセリンの 水分を、土のような ものに しみこませて 固く したら、 安全に 持ち運べるはず。これは いけるぞ！〉
That’s it! If liquid nitroglycerin is soaked in dirt is hardens, safe to carry. This could be good!
「ダイナマイト」の 誕生でした。
Dynamite was created.
ダイナマイトは、今までの 爆薬に くらべ、パワーも 強く、持ち運びも 安全でした。
Dynamite was about as powerful as explosives until then, but much safer to carry.
そのため 世界中の 国や 会社に よろこばれ、大人気となりました。
Thus, countries and companies around the world were delighted, and it became popular.
p. 188
ノーベルの目指した、《爆薬をいいことに使いたい》という願いがこれで叶うかのように見えました。
Nobel’s aim was “I want to use explosives for good things”, with this his desire seemed to come true.
ところが。。。。。。再び戦争が始まると、夢は無残にも打ち砕かれたのです。
However …… When war started once more, his dream was cruelly smashed again.
ダイナマイトは、戦争で人を殺す武器としても使われ始めたのでした。
In the war, dynamite began to be used also as a deadly weapon.
「平和への願いは叶わないのかーー」ノーベルの心は深く傷つき、年を撮ってからも悩み続けました。そしてーー
“Does my wish for peace not come true…?” Nobel’s heart was deeply hurt and he kept worrying as he grew older. Finally …
１８８：
ノーベルの 目指した、〈爆薬を いいことに 使いたい〉という 願いが これで かなうかのように 見えました。
Nobel’s aim, to want to use explosives as a good thing, with this seemed to come true.
ところが…ふたたび 戦争が 始まると、夢は 無残にも 打ち砕かれたのです。
However, again with the start of war, his dream was cruelly smashed.
ダイナマイトは、戦争で 人を 殺す 武器としても 使われ始めたのでした。
In war, dynamite was again starting to be used as a weapon to kill men.
「平和への 願いは かなわないのかーー」
Will my wish of peace never come true?
ノーベルの 心は 深く 傷付き、年を 取ってからも 悩み続けました。
Nobel’s heart, even after taking years, would continue to be deeply troubled.
年をとる is a fixed expression meaning “to grow old”
p. 189
なくなる前に、一通の手紙を残しました。
Before dying one letter was left (to be written).
『私が発明で得たお金を、毎年平和のために働いた人に与えてください。
"Please give the money I earned for my invention every year to a person who has worked for the sake of peace.
賞を作り、賞金として差し上げてください』
Please create a prize and give it as a monetary award."
こうして「ノーベル賞」は生まれました。
Thus the “Nobel Prize” was born.
ノーベルは未来に願いを託したのです。
Nobel entrusted his wishes to the future.
（終わり）
(The End)
The wikipedia article on Alfred Nobel has an interesting story concerning the motivation for the prize creation:
In 1888, Alfred’s brother, Ludvig, died while visiting Cannes, and a French newspaper mistakenly published Alfred’s obituary.[4] It condemned him for his invention of military explosives (not, as is commonly quoted, dynamite, which was mainly used for civilian applications) and is said to have brought about his decision to leave a better legacy after his death.[4][16] The obituary stated, Le marchand de la mort est mort (“The merchant of death is dead”)[4] and went on to say, “Dr. Alfred Nobel, who became rich by finding ways to kill more people faster than ever before, died yesterday.”[17] Alfred (who never had a wife or children) was disappointed with what he read and concerned with how he would be remembered.[18]
ノーベルの めざしだ、《爆薬を いい ことに 使いたい》と言う 願いが これで かなうかのように 見えました。
Nobel’s said aim was " i want to use explosives for good" and it seemed that wish came true.
ところが…ふたたび 戦争が 始まると、ゆめは むざんにも うちくだかれたのです。
Even so… War once again began and his dream was destroyed.
ダイナマイトは、戦争で 人を 殺す ぶきとしても つかわれはじめたのでした。
In war, dynamite also began to be used as a weapon for killing people.
「平和の 願いは かなわないのかーーー」
“Is my dream ruined?”
ノーベルの 心は 深く きずつき、年を 取ってからも なやみつづけました。
Nobel’s heart was deeply wounded and as he grew older he continued to be troubled.
そしてーーー 亡くなる 前に、 一通の 手紙を 残しました。
Finally… Before dying, one letter remained.
『私が 発明で えた お金を、毎年 平和の ために 働いた 人に 与えてください。
"Please give the money I earned every year with my invention to a person who has worked for the sake of peace.
賞を 作り、賞金として さしあげてください。』
Make a prize and please give them the prize."
こうして 「ノーベル賞」は 生まれました。
Thus the Nobel Prize was born.
ノーベルは 未来に 願いを たくしたのです。
Nobel entrusted his wish for the future.
終わり。
End.
１８９：
そしてーーなくなる 前に、一通の 手紙を のこしました。
And finally, before dying, one letter was left.
「私が 発明で えた お金を、毎年 平和の ために 働いた 人に 与えてください。
Please give the money I acquired with my invention, every year, to a person who worked for the sake of peace.
賞を 作り、賞金として 差し上げてください」
Please give an award as a monetary prize.
そうして「ノーベル賞」は 生まれました。
Thus birthed the “Nobel Prize”.
ノーベルは みらいに 願いを 託したのです。
So it is that Nobel trusted his wish to the future.
（おわり）
fin
As we have finished our book now, I will go on with a (slightly) less scientific book on miracles happening to hamsters in Strasbourg in the Christmas season.
The main verb in this sentence is the active transitive verb 残しました（のこしました）meaning:
‘(he) left (something), (he) bequeathed (something), (he) left (something) behind’
and not an intransitive verb (or a passive verb) as suggested by the translation
‘(a letter) was left, (a letter) remained (to be written)’
Note the difference between the transitive and intransitive verbs 残す and 残る:
残しました（のこしました）
is the polite past form of the verb
残す（のこす）
which is a transitive verb (i.e., a verb with an object) meaning
‘to leave (something) behind, to bequeath (something)’
the ‘something’ in this case being ‘one letter’,
as indicated by the object particle を after 一通の手紙（いっつうのてがみ）.
This is not the same as
残る（のこる）
which is an intransitive verb (i.e., a verb without an object) meaning
‘to be left behind, to remain, to be left over’
for which the polite past form would be
残りました（のこりました）
although this is more often seen in the -te form + いる as
残っていました（のこっていました）
where the subject of the sentence might be leftovers after a meal, or a task remaining to be done, etc., followed by the subject particle が.
Putting the pieces together:
なくなる 前に（まえに） before dying
一通（いっつう）の 手紙（てがみ）one letter
を [object particle]
残しました（のこしました） (he) left, (he) bequeathed, (he) left behind
giving the meaning:
Before dying, he bequeathed one letter.
Before his death, he left behind one letter.
Congratulations on anyone that made it this far! It seemed like it got a little quieter as the months went on but I really appreciated being able to see other peoples translations to compare. On to the next!
Working late tomorrow but I will be putting up a thread for wrapping up and final comments as well as a poll to click to say you’ve finished the book!
I’ll also put up a thread for anyone who wants to finish off the additional spreads that we didn’t finish from the start of the book.
I’m going to try to read the additional spreads but I’ve not managed the last 3-4 pages due to exhaustion from my drive! So may translate but not post.
Today is finally the day! 
I am so glad we’ve all made it this far, what an awesome group! Thank you especially to those who posted their interpretations and translations daily, they were invaluable. 
I hope to see everyone in the next book club (my books just arrived today!) 
