Vincent rubbed the back of his head. The furnace glowed with a visible heat, and beads of sweat crept down Jane’s front, tickling as they went. The apprentice finished blowing the bowl and deftly drew a stem from the hot glass. His face was flushed from the heat, and sweat matted his reddish hair to his head. He did not break from his rhythm or let his attention waver from his business.

Jane marvelled at the regularity of his actions. ‘What causes the bubbles in the glass?’

M. La Pierre ticked off reasons on his fingers. ‘Air. Change in temperature. Impurities.’

Vincent murmured to Jane. ‘I wonder. . . . If any impurity will show, might we control which ones do?’

‘I would think so, to some degree, else they could not create glass paperweights containing swans or bubbles.’ She considered this as they watched the apprentice blow yet another in his seemingly endless stream of goblets. M. La Pierre seemed disinclined to say anything else. ‘What do you think would happen if we cast a glamour inside the glass as it is being blown?’

Vincent tucked his chin in, and his eyes narrowed in thought. ‘Intangible as the glamour is, I am not certain that it could have any effect. And yet, glamour changes when passing through the glass of a prism, so the two must have a connexion.’

‘I would be curious to see what happens.’

The glass maker tutted and shook his head. ‘We will try it.’ Jane felt certain that he disapproved of the notion and was agreeing because of the funds they offered, but she hardly cared at this point.

M. La Pierre waited until his apprentice had finished with the last goblet and beckoned him over. ‘Mathieu, this gentleman and his lady want to try casting a glamour while glass is being blown. You will assist them until such a time as the task is beyond your skill. I want no repeats of your attempts to be an artist. Keep the craft clean and do the job.’ He cuffed the apprentice on the back of the head. The boy took the blow as if he were well used to this. ‘Understand me?’

‘Yes, Father.’ Mathieu bobbed his head in assent.

Jane could not feel that it was truly necessary for M. La Pierre to discipline his son in front of them. She might resign herself to such casual disregard, but determined that she would never treat her own children with so little respect.

As La Pierre stalked away, Mathieu lifted his head and wet his lips, acting as though nothing untoward had happened. ‘May I see the drawings?’

Vincent pulled them out of his coat pocket and handed them to the young man, who drew off his heavy leather gloves to take the papers. His left arm had a healing burn that showed just below the cuff of his sleeve. Jane blanched at the thought of the molten glass touching his arm.