hebrew - Is there a reason or pattern as to when the Torah uses אֵת instead of אֶת?

I noticed a mix of the two forms of the Hebrew objective marker commonly pronounced אֶת. in the Torah. (There is no English translation of this word. It is used only to notify that an object follows this word.) Usually the word אֶת is used with a segol, but there are some places where אֵת, with a tzere is used. An example follows:

Exodus 35:13-15 (The 3 verses are cited together, and a colon separates each of them):

אֶת־הַשֻּׁלְחָ֥ן וְאֶת־בַּדָּ֖יו וְאֶת־כָּל־כֵּלָ֑יו וְאֵ֖ת לֶ֥חֶם הַפָּנִֽים׃ וְאֶת־מְנֹרַ֧ת הַמָּא֛וֹר וְאֶת־כֵּלֶ֖יהָ וְאֶת־נֵרֹתֶ֑יהָ וְאֵ֖ת שֶׁ֥מֶן הַמָּאֽוֹר׃ וְאֶת־מִזְבַּ֤ח הַקְּטֹ֙רֶת֙ וְאֶת־בַּדָּ֔יו וְאֵת֙ שֶׁ֣מֶן הַמִּשְׁחָ֔ה וְאֵ֖ת קְטֹ֣רֶת הַסַּמִּ֑ים וְאֶת־מָסַ֥ךְ הַפֶּ֖תַח לְפֶ֥תַח הַמִּשְׁכָּֽן׃

Is there any reason for using אֵת, which is less common? Some thoughts that I have excluded:

• End of verse only? No, b/c verse 15 has it in the middle of the verse.


• Used only when the next word is a noun followed by another noun that has a definite article (in Hebrew, הַ) which acts as an adjective, as in אֵ֖ת לֶ֥חֶם הַפָּנִֽים׃ ? No, b/c The beginning of verse 14 starts וְאֶת־מְנֹרַ֧ת הַמָּא֛וֹר which has the similar construct, but uses the word אֶת

These are the only 2 patterns that I could think of. Are there any other possible reasons or is this just based on mesora and there is no reason at all?

Answer

When the word stands on its own, with its own trup-mark, it's אֵת, with a tzeireh. When it's attached to the next word with a dash and therefore does not have its own trup-mark, it's אֶת, with a segol. I think I learned this in high school; unfortunately, I don't know a more precise source.

I'm not sure what would be the underlying reason behind some instances getting their own trup-mark and some not. It might have to do with putting a little bit more emphasis on the direct-object status of what follows.