What does "by Purity is signified" mean in the following paragraph:<br/><br/>The three essentials of the English language are: <b>Purity, Perspicuity </b>and <b>Precision. </b><br/><span style="background-color:rgb(192,192,192);">By <b>Purity </b>is signified</span> the use of good English.<br/><br/>Does this mean that they by this term are trying to signify the use of good English?