Help on a vintage pattern

[Trinavo]

Hello! 
need help with this vintage pattern. Can someone please translate to modern crochet? 
 

Foundation Row: 1 tr. into 3rd ch. from hook. * 1 ch., miss 1 ch., 1 tr. into next ch., rept. from " to end. - (87 sts).
Turn with 3 ch

 2nd row: 1 tr. into first tr., 1 ch., miss 1 ch., 1 tr. into next tr., " 3 -ch., 1 d.c. into each of 4 dbl. tr., 3 ch., 1 tr. into next tr., 1 ch., miss 1 ch., 1 tr. into next tr., rept. from * to end
 

i understand the foundation row but for some reason I don’t understand the 2nd row. 
 

Thank you for any feed back

 

[bgs]

Might be an error.  I dont see how you can 

 1 d.c. into each of 4 dbl. tr.

when there are no dbl tr in previous row to work into.

[Granny Square]

Welcome to the ville!

I think this pattern may be written by a UK pattern writer so there are some very slight differences, but other than that I wouldn't consider this out of the ordinary--this is pretty a fairly conventionally and 'modernly' phrased.  UK patterns usually say 'miss' where a US pattern would say 'skip' for example.  Double treble is more commonly abbreviated as DTR not dbl.tr., but really, I can't think of what else dbl.tr could mean. (in other words, slightly odd wording but not incomprehensible)

I have been crocheting a long time, and have used a LOT of vintage patterns, and although US patterns 100 years ago used UK stitch terms, they otherwise used pretty much the same phrasing as a pattern from a Crochet World magazine that rolled off the press yesterday.  Before WW1, pattern terms get pretty funky.  

Oops, Bgs just replied, I hadn't caught that there weren't double trebles in the foundation row, I was just focusing on weird wording, and hadn't noticed that!

UK patterns tend to say 'miss' where US patterns would say 'skip', and the abbreviations in your pattern are slightly different - example double treble in your pattern is dbl.tr. where in US it's more common to see DTR, but really dbl.tr. and 'miss' were the only thing that made me pause.  And if you aren't aware, the stitch terms are different - slip stitch and chain are the same, but there is no SC in UK terms, and the stitch names are 'promoted' 1 level:

US SC = UK DC

US DC = UK Treble ... and so on