The phrase "a long and constant" is correct and usable in written English.
It can be used to describe something that is both lengthy in duration and unchanging or steady in nature.
Example: "The project faced a long and constant struggle for funding, which delayed its progress significantly."
Alternatives: "an extended and steady" or "a prolonged and unchanging".
Like many people, I believed America's relationship with Christmas to be a long and constant one, nearly synonymous with the flag and bald eagle.
This disaster is the latest in a long and constant string of tragedies as migrants risk their lives to escape desperate poverty and violent conflict to reach refuge in Europe.
In this sense, the MMR vaccination decision was seen as a less compelling choice than others, which instead required a long and constant mental reasoning.
A long and almost constant series of success proved the wisdom and utility of measures which carried victory through the world, and at the same time secured the public safety and liberty at home; for by these means the people had always an inexhaustible fund of experienced officers, upon every emergency, untainted with the dangerous impressions which continued command naturally makes.
Neighbors at the time said the garbage disposal was on for "a long time" and "constant chopping sounds" were coming from the home.
Thus, Greece is becoming the first country that will reveal the political consequences of this plan through these elections, the results of which are threatening to create a long deflation and constant public dejection within the UN.
By contrast, the love affair between British opera fans and these works, Onegin especially, is long and constant.
"The Catholic Church through its long and constant teaching holds that ordination has been, from the beginning, reserved to men, a fact which cannot be changed despite changing times".
In part because of the time of year and fatigue with the long and constant campaign.
The main limitation of this study is that we do not know if the additional ΔEELV is recruited volume, volume that overdistends already aerated units with a long time constant, or viscoelastance and chest wall adaptation, as we did not use any imaging of the thorax.
We accommodate these results by adding two positive adaptation terms, one with a short time constant and one with a long time constant, to a standard model of perceptual switching.
