Halfcrown description query

[Cliff]

In Maurice Bull's "English Silver Coinage since 1649" he  shows the number of harp strings and billets per silver currency coin year/types in the "Varieties, comments etc" column of his description tables (eg 6s - 9b).  The billet count ceased wef George 1 and was replaced by a hts count, whilst retaining the harp string count (eg 6s - 5hts) and continued through George II, after which they stop.

Forgive my meanderings but what are hts's?

[1949threepence]

30 minutes ago, Cliff said:

In Maurice Bull's "English Silver Coinage since 1649" he  shows the number of harp strings and billets per silver currency coin year/types in the "Varieties, comments etc" column of his description tables (eg 6s - 9b).  The billet count ceased wef George 1 and was replaced by a hts count, whilst retaining the harp string count (eg 6s - 5hts) and continued through George II, after which they stop.

Forgive my meanderings but what are hts's?

Probably not much help, but I don't suppose there's an abbreviations page towards the back of the book, is there? 

If not somebody on here will know straight off, I'd bet. 

[Cliff]

Tried that Mike and thumbed through my motley collection of books to no avail. Also tried the web for any heraldic clues etc but no go. I recall I had to do quite a bit of fumbling about a while ago to find out what a billet is.

[Rob]

Try hearts. The Hanoverian shield has hearts on it as noted on the 1787 coinage, so would be appropriate for anything commencing with G1.

[Cliff]

Smack on the button, thanks Rob.  Plain as daylight now they're pointed out to me but it needed your expertise to open my eyes!