does this article sound good in English ?

[RoseSpring]

One of Edison's invention

When Edison was fourteen, he worked at a railway station. He worked only at night. However, Edison used to spend the whole day working on his experiments. As a result, he would usually fall asleep during his work time, and he was not able to answer any of the telegraphs sent from the other stations. The inspector, however, warned him several times and ordered him to transmit a special signal every thirty minutes to prove that he is awake. Edison did as he was told only for a few nights, then he got tired of that. Therefore, he invented a small machine that transmits that special signal automatically every thirty minutes. Yet, at one night, the inspector tried to call Edison but Edison did not reply. The inspector found it so strange, as the signals were transmitted regularly every thirty minutes. So, he went quickly to the station where Edison was working, and he looked through the window. There he found him in a deep sleep, while the small machine was sending the required signals regularly. In fact, the inspector was so pleased with Edison's work; however, he could not let him continue working at the station and dismissed him.

[Monticello]

Hi tasneemspring,

Your passage does read well and also "sounds good."

The only thing that I might suggest is a little variety in your use of the adverb, however: Generally speaking, when one uses the word however to mean either (a) in whatever manner or way, or (b) In what way. Used as an intensive of how, the word works easily at the beginning of a sentence. (Please see the sentence models given in the previous link.)

Please note that in your passage, the word however never has this meaning. In these cases, where it means nevertheless, the word works best when "tucked in between" a sentence (usually separating two clauses). For example:

Edison used to spend the whole day, however, working on his experiments.

By doing this, you subjugate the word to a lesser position where it does not detract from the main ideas of your sentence but rather serves to facilitate its overall fluency, while at the same time serving (here) to conjoin the two clauses.

(Please note the USAGE NOTE given for the previous link I've provided above. As you'll find from reading this brief note, there is no "hard and fast" "rule" against using however at the beginning of a sentence; consider it simply instead, a means for facilitating your expression.)

Above, I've just provided you with a model for making these changes throughout your text. Why don't you go ahead and try this out? I think that you'll find these edits effective for the reasons already given.

Finally, for the sake of variety, you might also consider using a synonym for the word however, i.e., nonetheless or nevertheless, every now and then. If you "pepper" these alternatives strategically throughout your writing (specifically, in your posted text, as well as, generally speaking, in all your writing), you'll relieve a certain degree of otherwise monotonous construction.

[RoseSpring]

Much obliged indeed Moticello, I just want to know if there are any grammatical mistakes concerning tenses like:

Therefore, he invented a small machine that transmits that special signal automatically every thirty minutes.

The inspector, however, warned him several times and ordered him to transmit a special signal every thirty minutes to prove that he is awake.

___ one more thing, in using however the way you have suggested, do we use semi colon before it and comma after ?

Much obliged and grateful,

Tasneemspring

[Monticello]

Much obliged indeed Moticello, I just want to know if there are any grammatical mistakes concerning tenses like:

Therefore, he invented a small machine that transmits that a special signal automatically every thirty minutes.

The inspector, however, warned him several times and ordered him to transmit a special signal every thirty minutes to prove that he is awake.

___ one more thing, in using however the way you have suggested, do we use semi colon before it and comma after ?

Much obliged and grateful,

Tasneemspring

Hi tasneemspring,

Concerning your highlight text above, the use of the present tense for both provides more immediacy about Edison's actions -- even though these have taken place in the past. Most English readers would understand the mixing of tenses here not as a mistake, but as a subtle means for providing Edison's subjective point of view.

Your second question:

In using however the way you have suggested, do we use a semicolon before it and comma after?

No. - a comma before, and a comma after -- as in the model that I provided for you:

Edison used to spend the whole day, however, working on his experiments.

One further thing: Please note that a space never comes in between a word and the punctuation mark that follow it:

one more thing, in using however the way you have suggested, do we use semi colon before it and comma after(Space deleted here.)?